Craigslist tool

Looking for someone to build a Java script Craigslist tool I need it to be able to work with my existing site. It's a classified site. I need it to work like this.... When someone logs in to my site they log into their account and they see all their listings they have posted. Then they open another window to open up craigslist. now back at my site, somehow they click this craigslist tool link and a small window opens up with their listings. Now when they go back to craigslist all they have to do is click on their listing and the craigslist post ad window will automate all their info. Hope it makes sense