Compiling Plaincart & Login system into new website layout.

Here is the story: I had customized the Plaincart & its admin cntrl panel and its working fine but the system doesnt have a user member login & register system. So i found another login system source code, and its working fine now but the user login system database doesnt link to the admin cntrl panel. For the website layout, i had design the layout using photoshop and finished slice it out to Dreamweaver. The problem that i facing now is i am not able to putting all the shopping cart & login system into the layout. Secondly, i want the login system link to the shopping cart system means that after a user member login to the system, they can purchase item with their user, and database able to record item that they had purchased before so that user can check it back. Admin also are able to check the user info and item that they purchased before from the admin control panel. Need the completed system by 22th-23th january 2011. I am hoping to pay usd100 for this project.