Corn starch good for absorbing moisture, & you can get oxygen-based sprays to get rid of the odor;
you may have to use the spray at regular intervals for a long time.

I would first have her checked by a vet and make sure she doesn't have a medical problem, then I would make the bedroom off limits at night. You'll need to use an enzyme cleaner to rid the linens of the odor but if it has seeped into your mattress you may be looking at buying a new one.
If you end up replacing the mattress, also invest in a water proof mattress pad/protective cover so you don't have to go thru this again.

Where is her litter box in relation to your bedroom? Is it difficult for her to get to it and are there any other animals in the house that may prevent her access to the box at night?

Cats are clean animals, if their litter box is dirty they will go elsewere, clean it everyday and your cat should be fine. also save on pet supplies http://www.drsmartphonemd.com/pet_discount

For one, it would be a good idea to have your cat examined by a veterinary care professional to out rule the possibility of a urinal track infection.

For the smell, though, I don't really know how to help you. Cat pee smell is one of the worse to get rid off. Chemical cleaning might be the only way to get all of it out.

I agree with the posts who suggested you consult a vet. My cat is prone to bladder stones. When she has them, she will urinate on the floor, carpet, etc., I believe this is to get my attention and let me know something is wrong. If your litterbox is clean, I would see a vet.

Rubbing Alcohol is wonderful for cleaning anything that's hard to clean like that. Just pour it on and shop vac it up. Good as new. If the pea is very very strong then the cats urine is concentrated and not drinking enough. I am in the mist of that nightmare now.

I had a male cat who was marking territory in the house. I became a big fan of Nature's Miracle Cat Urine Destroyer. It really works well...it saved a friends mattress too.

A mattress is pretty much a giant sponge.

Have you tried turning it over?

pet urine neutralizer like "just for cats" or "natures miracle. Then flip over..?

If your cat pees on the bed, understand that it's her way of saying something is wrong. She might be sick or stressed, or maybe she dislikes her litter box.
Bring your cat to a veterinarian to make sure it's not a medical condition, such as a urinary tract infection or kidney failure, causing the inappropriate urination.
Clean the urine on your bed thoroughly, because if your cat can still smell it, she might pee in the same spot again.

I read an article on cat psychology that said it may be a way to leave a scent so you can find your way home.....meaning you've been away...kitty thinks your lost.....wants you to come home.

We have a cat who just does this for some sort of unknown reason and is banned from the bedroom. She can never be allowed back, it is not always medical, some cats are just bad.

Clean the litter box twice a day! think about it, would you use a bathroom that hasn't had the toilet flushed for 4 days. Your cat feels the same way.

I agree the cat may be trying to communicate something.

Had a real cross eyed crooked tail Siamese years ago. If we didn't feed it on time in the morning it would P on our bed. With or without us in it. Same exact geographical spot even with new bedding. So we got up early and fed it.

No more P. :-)