Right away I can see a few things you could do.

You can lengthen them by adding additional fabric or even wide ribbon to the bottom using iron-on tape (no sewing!)

A fabric that matches pillows or something else in the room would be a good option for doing the above idea.

You can shorten them using the iron-on tape as long as you can measure a straight line!

You can fold the tabs over and tack them to the back w/ a simple stitch or two to create more of a rod casing and thereby shortening them a bit.

Hard to see where the bottom of the sill is.

Buy ready-made ones that are too long, and take them to the dry cleaner. Most cleaners have people on staff that sew, and they can hem them for you.

If you want to keep the ones you have (and they seem to work fine with the carpeting color, and are okay with the wall color), have them shortened to the bottom of the window, so that the length looks intentional.

One other thing you might try, tho this will seem bizarre. Take a panel and turn it upside down, so that you use the bottom hem as the rod pocket. You might have to open a couple of stitches if the side seam overlaps the bottom hem. Put it on the existing rod, and see where the panel hits. I am betting that if the tabs were removed on the now upside-down drape, the length would be right. The drape would also hang so that you didn't have the gaps at the top with part of the trim showing, etc.

You could also see if you could do the same thing with the top of the curtain instead, as it appears that there is a wide enough hem there; the only issue might be that the buttons might be sewn through the hem, so you would have to take those off to open the hem.

As suggested, you could also add a panel of fabric to the bottom, but if you don't sew at all, it might be a lot to tackle. You can use the iron-on tape to attach it, but you have to be able to cut the fabric correctly and it will have to be hemmed all around - perhaps more time consuming then just flipping the panel over and cutting off the tabs that end up on the bottom.

O.K., here's a pic with the curtains open so you can see the bottom of the sill. Sorry the lighting is bad.

IMHO, I really don't like seeing the white trim thru the tabs. It looks like you could raise the rod enough to fix this, but that entails a lot of wall patching and is a pain. Try pinning the tabs to the back on one pannel and see how that looks.

And/or you really don't need to shorten them much to hem up and so could just measure up to the bottom of the sill trim, fold up the current hem and iron on the tape. The extra fabric in the hem will help weight the hang of the curtain and shouldn't be noticeable that you just folded them up.

Decide what you want to do at the top of the curtain. If you like the top the way it is, then just hem up the bottom yourself using the tape or find a seamstress to do it for you. A hem like this is so easy to do by hand that it would be worth learning how to do yourself. A visit to a fabric store and a few questions asked of the salesfolk there and you would be good to go!

Maybe this will work: Remove the tabs rather than moving the rod. Turn your fabric top edge over in two-inch increments enough to pull up the curtain bottom to the window sill. Then sew your rod pocket.

BOTH!

For a "full length" (ie, to the floor) treatment the panels should end 1/4-1/2" shy of the floor/carpet. For the treatment to end logically and "make sense" visually when you have "outside mounted" panels (rod is mounted outside the trimwork) the panels should end in line with the "apron". The "apron" is the piece of window trimwork below the sill; it's the piece that finishes the "casing".

You have a couple of options:
1.) Move the rod higher or leave it where it is and customize the panels to suit its placement.
2.) Shorten the panels to the apron.
3.) Lengthen the panels so they fall within the recommendations for full length panels.
a.) Let the hems all the way down and see if there is enough extra in the allowances to accomplish the lengthening; Face the backside of the hem allowance.
b.) Let the hems down and determine how much of a border you'd have to add on to achieve a pleasing proportion and have the necessary amount to nicely weight the lower hem, BEFORE adding drapery weights to the bottoms of any vertical seams.

(personally, I'd probably opt for 3a/b. I think the lower sill (relative to the floor is going to make for an ungainly "look" relative to the rest of the room, even if you follow the basic rules.)

Glad you asked, huh? ;)

Thanks for all of those suggestions! You all are very creative. My MIL can sew, so I'll see if she can let the hem out. DH can move the rods and do some patching and painting at some point. Also, I purchased these curtains at JCP. They actually have valances to go with them. Do you think I could use the current rods for the valances then add an inexpensive rod underneath for the panels? I could position the rod to the trim and lower it so that the panels would touch the floor. Of course, I'd have to make sure the valance would cover up the tabs on the panels. They're 17" long. The tabs on my curtains are about 6 1/2" so that gives me 10" to play with. Does that make sense?
Otherwise, I really think full length panels would look best, so I may have to bite the bullet and include new longer panels on my "want" list for our budget.

Here is a link that might be useful: Valances

I don't know if these is right or not but if the panels are decorative and not for privacy you might try 3 panels. It seems a little much in the middle. I vote on getting the longer ones and hemming them, raising rod, and trying 3 panels.