Hopefully someone here on RG will give you a good specific recommendation. Until then, you may find this review of interest: http://pabmabs.com/wordpress/?p=3597
And if you want to explore other possible sources for anti-c-fos we list many:
I am working with the antibody c-fos (cat.No.226003) from synaptic systems. (www.sysy.com) on mouse and rat brain tissue with good results. This antibody works also on monkey, ape, dog, cow, pig and human.