I just took a look on the Reaper forum and it does not have the notation feature, but it does record MIDI. So if you wanted to, you could record the MIDI data in Reaper and then import it into another program that has music notation.
If not, check out some of the Cakewalk products. They have a wide range of programs and most of them (if not all) should be able to do that at much, for much less $$$.
I just did a quick search and found this one:
Amazon.com: Cakewalk Music Creator 4: Windows: Software
Here's a promo video for it:
Cakewalk Music Creator 4
-tkr