Ideal thing to do would be to open an account for yourself.
Meanwhile, if there is reporting to her from ebay on Form 1099 than she needs to report it on her tax return but deduct the entire amount stating received as nominee and providing your SS# on the tax return. So, the net effect will be zero on her tax return and you will report the income.
This is ok for short term. But, you do need to work on setting up an account in your name or your business name.