vTiger : create new Timesheet module

I need a "Timesheet" module that will be accessed from the customer portal. The user experience should be as follows : 1. User logs into customer portal 2. Selects "TS" icon 3. User sees a widget with list of timesheet line items 4. User clicks new timesheet. 5. Show user a picker where they can pick Yr/Month/Week 6. Show user a One week schedule (Columns: Date/Hours/Notes) 7. User can Save for future editing OR Submit for approval and no further editing This is fairly urgent and so I need someone who understands this process and has done module development many times before.