Offers Valuation and reverse auction help

[abbynormal]

We're looking to valuate two web sites we run, each with six figure annual revenues.

We also are seeking help in running a reverse auction that brings in some of the people in our industry who would likely be excited at the opportunity to acquire our brand.

Could someone point me in the right direction of a company specializing in brokering web based businesses with real revenues within a niche industry?

Thanks!