I am using HTC wildfire. Is there any possibilities to upgrade mobile processor so I can run Android 2.3?
You cannot upgrade the processor, however you can upgrade the kernel.
Find your device on forum.xda-developers.com and read, read, read, read, and read some more.
It may sound scary, with the risk ofx bricking your device, but I assure you it is much easier than it would be to replace the processor.
If CyanogenMod 9 is ported to your device, then you could even have a 4.0 update.