I will answer your questions one by one here:
1. copy the existing data to the cy7c63310 without changing it. do i have to change only i/o port from pcb.
A. It is not possible to use the same hex file. There may be changes required on the PCB also.
2. or Should i re-programme to cy7c63310?
A. Yes, the firmware has to be redone for CY7C63310.
3. do you have a tool that converts automatically?
A. Such a tool is not available with us.
4. our company doesn't have enough people to do asm, is there another service company?
ofcouse all have all source problom
A. We are not aware of any other company who can develop firmware in asm.
5. the best way is there is a way to get about 500pcs
A. You can post your development requirements in this forum. Someone who can develop in asm can respond to your request. You can take it from there.