How can I help a cat that ate clumping kitty litter if you're unable to get medical attention?

A few days ago I noticed my 2 yr old cat (male) acting funny as far as his eating, drinking, & bathroom habits. Two days ago, I found some kitty litter vomited up in my bath tub. All in the mean time, he was attempting cough up, what I thought were hairballs, more & more frequently...today he added rapid sneezing. He really has no interest in food at this point, but he seemed to enjoy a belly rub today. (WEIRD!) During his rub I felt a hard peanut sized knot in his belly. I'm a disabled Gulf Veteran & a single mom with too much month at the end of the money! It would DEVASTATE my special needs son to put our furry family member to sleep. What can I do to help my cat pass, or bring up the litter so he can be ok again? PLEASE HELP