Foam head issues

I have one of those foam heads that are ridiculously small for an actual head; the cheap ones you get at a wig shop or craft store. I know I can foam it out, but I'm not sure precisely how to go about this.

I DID have an idea to make a sort of helmet over top my head out of plastic canvas, the stuffing up under it over top of the foam head to keep it in place, then marking a spot for noses and such. I could draw a quick pic. Woop, found this (http://fursuit.livejournal.com/1843859.html), but what do I do about hair and such?

I'd buy an actual fancy head if I didn't blow a tire earlier this week. I'd have to wait quite a while until I can afford to get one...

Any thoughts or tips? What parts of my head do I measure?

Thanks in advance!