As far as patentability, it`s hard to determine whether your idea is patentable, or not, with the info you provided. (Although, I understand your reluctance.) I will say that patents do exist in your category--Ebay is currently in a patent battle with another company (forget the name) about online auctions. However, maybe you have another take on it that is novel and nonobvious. So, there are some fine books and guides out there. I`d consult with them. Or keep an eye on more posts.
Also, if you have no experience with the web, I`d try to learn more and start working your network. You found your weakness. Find someone that has those skills and believes in your idea to partner with.
One last thing--I`m glad you picked StartUp Nation!
I have been selling heavily on Ebay since 1999. Many competitors have come and gone since then and most have failed miserably. I don`t say this to discourage you...simply to suggest that you will need something very unique in functionality and purpose....just another auction site (even with a niche market) is going to be very tough.....you might even be able to use Ebay or an Ebay store as a tool....not sure what you are envisioning