I know you are afraid to take them out of their wrapping, but besides what everyone else has said, all valid points mind you, think about this:
Would you drop over a thousand dollars for something you have never seen an actual picture of? Something USED at that?
My mom is in the same boat trying to sell a high dollar embroidery sewing machine. She is stuck on a value that she paid for it, had estimated, thinks it is worth, etc, but she has listed it several times and not had any luck. Ebay is a strange "place". Things that should go for a fortune sometimes don't will things that seem to be "worth" nothing sell for a lot of money.
The bottom line, as previously mentioned, is that you are only going to get what others value it at. You said you always have watchers? Perhaps e-mail them and offer them a second chance bid, or see what they are willing to pay for them? You don't have to sell it if they don't get a price you are interested in.
Also, you said that your grandma would be upset? Upset at what? Her curtains were not able to pay for your whole computer?? This opens up a whole new spectrum of questions - Like, can you not afford the computer with out selling the curtains? If not, should you be buying a computer? And, if money is tight shouldn't you just take what you can get?
I am sure there is some personal value to your grandmother, as most older people in particular hold tightly anything for which they have purchased. But whats it to you? (Did she give them to you, ask you to sell them, is she giving you the money, what?) If SHE doesn't want to sell for any less that makes sense, and perhaps you should wait till she changes her mind or no longer has a voice in the matter (trying to be tactful). Or, sit down and discuss the idea of "value" and "market".
Regardless, you have a custom item, it is custom to YOU (or your grandmother in this case), people who pay for custom things never, or rarely, get the value that they put into them back. (I.E. Just because I customize my car with a special stereo, seats, etc. doesn't mean that I can jack up the price and expect someone else to pay for items that I feel makes my car more valuable. Because it is just that, valuable to ME.)
Not trying to rant, just help you understand.