go with what you can afford. rebuilt transmissions are very reliable so dont listen to everything you hear. you can get very good warranties on rebuilt transmissions from Jasper and others. prices will change depending on the length of the warranty and companies. shop around. you can even get very reliable transmissions out of junk yards and save several hundred $'s.
Check the yellow pages for a local transmission repair shop that is certified by ATRA. The logo should be in the ad. If not, call. Get several estimates for the repair. It may not need replacement, since you don't say what the problem is. If a tranny is rebuilt, all of the worn parts are replaced, and it will be just as good as a new one. Many shops give a minimum 6 month warranty. ABOVE ALL, do not go to a transmission store like AAMCO or any other national chain. They grossly overcharge for parts.
I don't want to give you advice and watch it backfire because you have children, but I have an '84 Cutlass, I put a refurbished tranny in it for 1300, and a refurbished engine in it for 2300.I have been driving the car for 3 years since. No problems. Just make sure that the tranny is refurbished and not used or out of a junk yard. $1,000 sounds a little cheap for a suburban. Good luck.
Anything could cause your check engine light to come onIve heard of gas caps being loose and it causing check engine light to come on Change your hoses and have your chip cleared at auto-zone and if it comes back on again then you know its not that and to go have it checked again