what do you mean by "clogged". Do you mean the distribution pipes are clogged or the land doesn't percolate anymore?
If the pipes are clogged you probably have a busted baffle in the septic tank. You can get the pipes snaked out and it ain't that expensive. But the baffle problem (if that's it) will force the issue to happen again.
If the land doesn't perc - you're screwed and will have to get a mound system or depending upon the state law maybe even a holding tank.