Auction Site Project (not an ebay type auction)

Hello, Please read the description of what we need exactly; I am going to hire someone very quickly and need to find someone that can do exactly what we need. First of all, we do business liquidations and we what we need is an auction site that will allow us to list the items for each auction (similar to the way it is done on equip-bid or aacbid or samlilly) and have them run through the auction, with a quick and easy way for bidders to sign up. I really like the design of samlilly better than I do the other two, but the backbone is what is really important. I do not know what scripts these sites are using, but if you can find these scripts and they are not too expensive, include information on that in your bid and I will purchase those for the purpose of completing the job. I want to be able to change the starting bid amount, I need to have the ability to have an unlimited number of auctions running at the same time, I need the ability to change the starting bid amount, I need the ability for the site to automatically generate invoices at the end of the auction and add in the buyer's premium and send this to the purchaser. I also need the ability to charge either a buyer or seller premium or both and set the rates for these. If you can find the scripts to do this and install them for me (and the scripts aren't too high themselves), I'll pay you 100.00 just for finding them(not including the price of the scripts themselves), no problem (even if they are free scripts and they install quickly, it's worth my time). I don't really need a lot of layout work or graphics; I'm just looking to get the backbone done and make it usable so we can make the changes we want and get going. I do have a fairly tight time frame and would like to get something up and going quickly. Thank you and please don't hesitate to ask any questions.