If the program in question has not been written in 64 bit then there is nothing you can do. The majority of software is still 32 bit which runs fine. Most programs do not need to address the larger RAM configurations that 64 bit OS's support. If your 32 bit version is OK then carry on with it is my opinion.
Some programs still don't have 64 bit versions. 32 bit applications work fine even faster. 64 bit application can use more RAM and that is of significance sometimes.