Foam won't help dispurse the heat, if anything it will increase it.
Try filling the gap with a copper shim, they sit around the chip giving greater coverage.
What coolers are your using.
My advice is to get some Artic Silver II heatsink paste, and get yourself a decent cooler - preferably an Alpha or Thermalengine, or the other options available are to make up a water cooling system or buy a peltier, that should bring the temperature down a bit.
You should invest in some system cooling also. Retracting the heat away from the chip is no good uless you can get rid of the hot air that is now inside your case. I recommend that you get some 80mm - 120mm fans for your case, usually 80mm holes and casings are built into cases for the front and back, one sucking air into the case at the bottom and the other extracting air from the back.
Slot coolers are also available, they take up a slot where your PCI/ISA cards normally reside. These although cheap, can really reduce system heat.
With regards to the 92mm fan on a FOP32, the only way to do this is to get some metal sheeting and create a tunnel for the air starting at the size of the heatsink going up to the size of the fan (leave the heatsink fan on also). Or get some tubing from a air duct or washing machine/tumble dryer air duct.
your chip should touch but if there is not enough pressure from the HS to make a good connection try bending the bracket that hold it down backwards a little so there is more resistance-to put more pressure on the chip maybe itll make better contact-use thermal grease also Artic Silver 1 or 2 reccommended. Once you get a good contact you should see a good temp drop
i don't really think air getting into and out of my case is a problem, i have cut 3 120mm holes in the case and used ys-tech fans, my heatsink, a global win fop32-1 is old and needs replacing soon so i probably will go for something copper. i am thinking of another globalwin the cak38 or i might just get the coolermaster heatpipe and put a 60mm on it