Is there a way to know how many requests WAMP can handle in a second. And is there a way to increase that?
By WAMP i mean the package software installed on the local machines
As Amber said, it depends on the specs of the server. However, you can do benchmarks with ab.exe, located in the apache\bin directory.
More info on Apache Bench: http://www.petefreitag.com/item/689.cfm
It all depends on your server specs, what other processes are running, how intensive your request handling is, et cetera.
In other words, there's no specific answer to your question. For tips on tuning performance, you might want to ask on ServerFault.
I have heard figures ranging from about 10-50 for an unoptimized webapp, > 100 && < 500 for an optimized webapp with database optimizations, and 1000+ for a webapp behind a load balancer, some caching, and 10000+ with proper horizontal and vertical scaling and tinkering with your framework/language to squeeze every last bit of performance out of it.
These are just estimates off the top of my head (and probably wrong, but that's the point of guestimation). They will differ based on what you're serving, whether you've configured your stack to squeeze performance, whether you've optimized your code, the limitations of your hardware and bandwidth at this point and whatever else life has to throw at you.
ab
against it and find out!