Now that you've had scorn heaped on you for using AOL, I'll answer your question:
Nope. There isn't a way to increase the size of the fonts in the filing cabinets. I don't know about the IMs, because I don't use them at work. Furthermore, the AOL Tech for Mac is atrocious. You might consider a third-party e-mail software like Mozilla's Thunderbird, but there appear to be quite a few glitches between AOL-Thunderbird on the Mac platform - all solely due to AOL, I'm guessing.
The AOL Mac browser is slow slow slow and often doesn't bring up the entire web page. I have to keep the AOL e-mail name for our small office (have had it for 11 years now), but I use the Safari browser (not too impressed - it crashes all the time), or Mozilla browser.
Sorry I couldn't be more helpful in getting a solution to your problem for you.