Didn’t check yet Mac version on OSX 10.9. I just learned that one can update firmware to 435.10 from tgFX build 3625. However there is no tgFX build 3625 Mac binary to download as of this time. So I am kind of walking in circles here.
Avrdude is buried in the latest Arduino package, version 1.5.7. Unzip the app and right click to show package contents (these are OSX instructions, other platforms may be different). You can find Avrdude in Contents/Resources/Java/hardware/tools/avr/bin/avrdude