If you want to do a very quick job, I recommend downloading QuickArial:
http://www.eq2interface.com/download...fo.php?id=3230
It moves all of the font definitions for US/EU localized versions into a single file so you can edit them easier, and changes everything to use system fonts so you don't have to use BuildFont.
Just change the PointSize, FontName, and Algorithm (Simple or Bold) for each font line, leaving Name alone.
Most of the UI uses FontZapf15, so that's the one you should increase first.
If you don't like Arial then you can switch it back to Times New Roman (and Bold), which is pretty close to the original font.
Good luck!