Looks like it might be Ariel Bold or Helvetica Bold or Medium. Sizes are hard to figure out on a monitor; use trial and error, starting perhaps at 10pt.
After much messing around, the font ended up being Verdana (bold) at around 13pt. I created a .PSD for it. If someone else could provide the original, that would be nice as well since mine is slightly off.
Attached are the original, new version, and the new version's .psd file.