The scenario that you are describing fits exactly to the use of PerformanceCounters.
You can create your own custom performance counters and monitor their behavior from PerfMon.
You can wrap your relevant business code with counters - such as avarage response time, throughput/sec etc..
I've found a nice article about Custom Performance Counters here in CodeProject:
Using Custom Attributes to Create Performance Counters
You can find a lot more examples on the web.