Help needed to set reserve on eBay auction - advice needed

This is an unusual project, but I've come to Freelancer because I have a big problem with my eBay auction. When I placed the item for sale I wasn't given the option to set a reserve. At the time I wasn't particularly concerned as I figured my listing would get bid up, but now I am deeply concerned I will lose my item, the bid is still very low AND to make matters worse... I have contacted eBay and they say I can't set a reserve this late (bids have already been placed) and if I cancel the auction I have to sell to the current top bidder. I also have a 100% positive feedback score so I fear that I will get negative feedback which will ruin my reputation. I'm looking to find someone with some experience (eBay acc with 5 or more feedbacks) to advise and help me out. Thank you.