Hmmmm, i'm curious as to why you don't have round brushes with PS7 being it the most common brush? Click on the brush tool in the tools palette on left side. Right click on your image. Click on the triangle in circle top right of that window. Select Reset Brushes. There should be round brushes (sharp and fuzzy). You can use that menu to append any other brush sets from the bottom of that list. There are a lot of sites for PS6 brushes but can be used in PS7 as well (a few listed below). You can also make your own brushes as needed.

Free Photoshop Brushes
brush sets for Photoshop
deepspaceweb brushes
hair brushes