I have a 1995 chevy astro van with 20,000 miles on it. when i bought it it came with a 5yr/50000 mile warranty?

so the middle of next year i will have no warranty.i was thinking of purchasing an extended warranty how do i go about doing this? do i find out from GM. the dealer i bought from is no longer in business.should i be leary of gm with their financial problems?also if i purchase an extended warranty could i bring my vehicle to lets say firestone,or a reputable garage nearby,and they will honor the warranty or will chevy be the only ones to honor it.PLEASE HELP!!