I think the girl is fine - but she sends mixed messages - she's trying to explain whiteyboard, but she's trying to be a little bit flirty - there's a long awkward pause at the end that needs to be shortened, and the moustache is really gimmicky.

Also, if you stick with the same girl (which I think is totally fine), you should have her wear a more professional outfit (not to sound sexist or anything). What's your biggest potential market? (offices i'm guessing?) You should have her match that - so for offices, maybe business slacks and a professional top. Right now she looks like a college student, which is fine if you're trying to cater for that market.

I can't believe no one has mentioned this, but it seems to me the most important thing is how well you can erase the marker. Assuming it works well you should demonstrate this. I simply will not buy a whiteboard without knowing how well it will work over time. Also, I've used Georgia Pacific Mark-R-Board which costs about 1/3 of your product and it works just fine. That made me chuckle when I read the cost comparison in your FAQ.