Here is also a program to solve the limited buffer as you've mentioned ,it is called SerialWatcher and you can download it from here :
http://www.pcremotecontrol.com/

about the formating problem you've mentioned you have to use some fonts like the 'System' font .if you have considered when you're typing in DOS in eg. '.' character will use a full matrix but in windows most of the TrueType fonts wouldn't do that , so the spacing looks diffrent try typing some characters both to dos window and to the MS-Word ,you'll see that some characters will use more space in DOS than the windows.

Best Regrads :
Farshid J.H.