Transmission concerns

I have a 92 LSL, great car! except the tranny is a bit tired. There is a bit of a hesitation when I first put it into drive, but the worst thing is between 2nd and 3rd gear there is a delay of about 2 seconds. I had the dealer check it out and they said I need to replace it and that the AT fluid was burnt. I doesn't smell burnt to me? I want to put off replacing this transmission as long as possible. The bottom line is the car still drives fine. Although, I know I will eventually need to do it.

My questions are:

Will it help if I change the fluid?
(I could put in sythetic, or an additive to standard ATF)

Should I add a cooler NOW or wait til the new tranny?

I know you don't have a crystal ball, but I'm thinking I may get 6 months or longer with the present tranny. What do you think?

Thanks
_Ken_