Was the module loaded when you looked at /proc/interrupts? I should have said something about that... it has to be.
If the module was in fact loaded, then the problem is the "assign irq to vga" setting that you said you couldn't find. Talk to your motherboard manufacturer (or system mfr. if you bought this all as a package) and get them to tell you how to get the BIOS to assign an IRQ to the video card. If they say you don't need to do that, tell them they're wrong.