Deltona, I'm wondering if it is even the SQL Server response time that is the issue. Have you investigated the IIS side? I've seen thread starvation issues where everyone assumed that the problem was database response time b/c the web server had low resource utilization (CPU, Mem & disk). You might try testing in a time window that you can be the only user (if possible), trace the SQL calls, count them, check their response time etc. I know that's tedious but it's a pretty quick task if you can isolate your utilization. If you can't, there are other roads to travel but they get a bit more complicated. The following counters are ones I've found very useful to diagnose IIS thread starvation. The definitions PerfMon provide should help but if not, I'd be happy to lend some guidance.
ASP.NET v2.05727\Requests Current
ASP.NET v2.05727\Requests Queued
ASP.NET v2.05727\Request Wait Time
ASP.NET v2.05727\Request Execution Time
.NET CLR LocksAndThreads\# of current physical Threads
ASP.NET Apps v2.05727\Requests In Application Queue
System\Processor Queue Length
