What OS are you using? Does SH3 run at the games stock resolution? Don't run the batch file for the Hi-Res-Fix unless you're using Win XP. You might try reading through this
http://www.subsim.com/radioroom/showthread.php?t=209346 thread and see if you can glean anything that helps. There are lots of other threads about this topic too. Even if you get it to run at that res it will be all stretched out of shape. You might be better off finding a 4:3 compatible res, like 1920 X 1440 perhaps.