Add autocomplete to an Applescript/cocoa project

I have a small program that was originally built in Applescript studio and then modified into a cocoa/applescript project that allows data entry into a few windows and then the creation of a Microsoft Word file from that data. In one window the user enters the client data (name, company, address, etc...) OR the user can get a list of clients that is created from Address Book (now Contacts) when the program is launched. When a user selects a client from this list all the relevant data (name, company, address, etc...) is filled into the form. The creation of the list takes too long and is clunky. I would like to simply begin typing the client name (in either the "Client" field or the "Company" field) and then have all the other data (address, email, phone, etc...) be autofilled when I press enter or tab etc... Similar to how webforms are auto-populated... Attached is the xCode project for examination as well as a vcf file with contacts for use with the program...