Tips on Buying Cars: Returning a Lease, warranty booklet, chevy dealer

Question
We have a Chevy Trailblazer that I have been anxious to get rid of as my Lease is up in 3 months.  2 days ago it started to make funny noises and we brought it to the Chevy Dealer...he told us yesterday that the Motor is blown.  The truck is 4 years old with 45000 miles on it.  Are there any options for us as the lease is up in 3 months, we were planning on getting rid of the truck and do not want to put $5000 into it.  We don't understand how this could happen to such a newer vehicle as we took very good care of it.  Please help!

Answer
I need some more info:

1) What year is the Trailblazer?  How long was the lease for?

2) Have you checked your warranty booklet- is there an extended warranty on the power train?

3) Have you had a mechanic other than one that works for the dealer look at the vehicle?

4) Do you have all the maintenance records for the Trailblazer?