New App for Case Management

My company currently uses a purchased application for case management and disability claims. We have been allowed to modify it for our needs, plus we have our own web based version that we have created - with the code (VB.Net). We are looking to create our own application from the ground up that incorporates all the necessary features from the apps plus additional enhancements. We will work the initial app requirements and the programmer chosen will work closely with our internal programmer throughout the project. We anticipate that this project could take 6 - 8 months to develop and would like only serious bidders please. Again, we have a good portion of code already developed that we may reuse in some fashion or tweak. Program must be able to run on XP/Vista and 2003 Server and coded in VB.Net.