2000 mercury sable TRANSMISSION?

PLS HELP,i recently took my car to the local ford dealer because it was not shifting gears.It would just rev really high until i let off of the gas. Well the dealer said all they could find was a bad transmission fuse, and that no matter what they tried they could not get the new fuse to blow. So after the diagnostic tests and the $6.00 fuse it ended up costing me over $100.00.Well about a week later the fuse blew again so i just changed it myself only this time it spilled all of its transmissin fluid, and the emmisions light is staying on. can anyone tell me what the problem may be.