Performance with VB & SQL server

I am consulting with a large Life insurance organisation.

The environment is: Life administration system built in Visual Basic (with a little Vis Fox)on SQL server. The OS is Windows NT.

Currently we have one data & application serer, althoughwe are looking at moving to one for data, plus two or more for the aplication.

Current stress point id the batch processing, which is taking 5 hours, and added to the backups look to fill our batch window. Online performance is fine, however, itobviously must not suffer.

The question is:
Where should we be looking to improve performance, and what would you use to measure performance?