Seriously, I thought you lived in Florida. How can you be freezing? Guess I was mistaken.
I live in Maine- we know freezing! Yes- drapes or shades- either has an R value and will offer some insulation. You can do an internet search on "r value shades" or "r value window treatments" and will find lots of information.
With shades, blocking the whole window provides the greatest benefit -so outside mount, with no gap. If you do inside mount the more space to the left and right of the shade the more of the insulation factor you lose.
Also with shades, the density of the fabric, the size of the cell(for cellular) the lining of the cell, all these impact the R value as well.
For drapes, again it is covering the whole window and the density of the fabric. There is such a thing as thermal lined drapes, they have a thick rubber coating on the back. Their specifid raison d'etre is to stop big windows from making you freeze. JC Penney is a very reliable source.
Good luck and stay warm!

Some area rugs over the hardwood floors would help in the winter. More important is how the room was built ... the quality of the windows, insulation in the walls, ceilings and floors and how the heating system is set up (location of vents/baseboards). Where is the cold coming from and where is the heat, you pay for, escaping to?