Looking to Rebuild our Classified Listing Website

We recently built: GentlyUsedBabyGear.com. Now that we are promoting the site and actually getting traffic, we would like to rebuild the site in the following ways: 1) Cleaner/Fresher Look 2) Maintain the classified listing portion, but build it on our own platform/database so that we can add fields, options, etc along the way. We are currently using an excellent wordpress plugin that is quite limited 3) Ability to eventually charge users of the site for certain features 4) Able to run ads or provide links within the classifieds that are specific to that classified listing based on tags that we determine to be relevant 5) the ability to create an e-commerce portion to the site. This site is built using Wordpress and we do not want to move off Wordpress. Please do not reply without samples of work that are a) in Wordpress and b) as similar to this project as possible.