Need Help On A Transmission Rebuild.

Well I think I should go buy a lottery ticked cuz I seem to have really good luck in the sense of beating the odds.
At 165K miles I had my tranmission rebuilt, replacing everything, and when I did that I put in a transcooler, and a transgo shift kit.
Around 185K miles I had the transmissions main seal give and I had it replaced under-warranty, during this time they decided to replace the torque converter also.
Well it is 195K miles and the torque coverter is starting to go. It began by getting an error code on my dash, with the OD light flashing.
I had the error code read and later diagnosed by the place I had it rebuilt and they are saying that the torque converter is begginig to fail. The place says they will work with me on some of the charges since this occurance is supposingly very rare but I am past my 24K mile warranty.
Since this will require pulling the transmission out I was going to ask you guys for reccomendations. I am wanting to make the tranmission a stronger beast and at the same time possible change some of the characteristics of it.
Here is what I am thinking.
I am wanting to change the gear ratio's in the AX4N to give the car more low end torque while not losing too much on the high end.
Here is my "theory"
In the duratec the power band is in the high end RPM, and by changing the gear ratio in gears 1 and 2 and possibly 3 I hoping this will allow more low end torque by allowing the engine to rev higher and in these gears.
currenlty the AX4N has a gear ratio of 3.98:1 for the duratec.

1st 2.771
2nd 1.543
3rd 1.000
4th 0.694
Reverse 2.263

Now granted that I am not sure what the limitations on putting different gears in the AX4N. This is where I am asking you guys for input. If anyone has information on this subject please share. I am looking for a lot of input on modifying the tranmission with the goals of transfering more power, being able to handle potential power output of over 300hp, and deliverying more torque.