I have the same case. What I did to improve air flow to my CPU is remove the metal plates behind the 2 bottom 5.25" drive slots. I'm not using a drive there, it's just that since the front is mesh and comes with built-in filters behind those covers, it gives the CPU more fresh air. I have a Freezer 64 Pro and, since it's a vertical cooler pulling air from the front of the case, I can put my hand in front of those 2 drive slots and feel cool air being pulled in. You can improve upon this by rigging a fan in that spot, as well. This should create a virtual wind tunnel between that fan and the rear exhaust fan, with the CPU fan right in the middle. I've considered doing this, but my cooling is adequate. Alternatively, if you're using a standard up-facing CPU cooler, consider installing a fan on the side panel above the CPU.
Pictures would be helpful.