If you are asking if Win 7 will slow your PC it is unlikely that it will. Your machine seems basically powerful enough to run it. You may get a benefit out of upgrading to 4 GB RAM if you want to use 64 bit Win 7.
The major difference is that 32 bit can only address up to 4 GB RAM but in reality can only use 3.1 to 3.5 GB RAM. 64 bit can address RAM configurations much higher than that. 64 bit Win 7 can address up to 192 GB RAM but Win 7 Home Premium appears to be limited to 16 GB and Win 7 Starter can only address 8 GB.