Budget of $0, with a list of features like that... You are probably going to have to re-think that one...
You could probably get something on Windows that does that (provided you already had Powerpoint, you could add screenmonkey to the mix and probably sort something out), however Mac's just don't have the wide spread developer base that is found on windows - so such specialty software is going to be hard to fine.
Macs don't tend to be used in the presentation arena too frequently either.