Hi April!
Those are great questions, but a little complicated to answer. I say that because there are factors to consider ... so, I'll make some assumptions.
Since you're using Google's ads, I'm going to assume you're looking to rank on Google primarily. Not that the others don't concern you, but Google currently commands the most eyeballs.
With that said, Google recently shoock up the Internet blogging world by devaluing all the free blog sites ... except their own of course. Which is where your blog currently sits.
So, the blogs that are now ranking higher are the ones hosted by Google and the ones on their own domains. Which means that if you switch it's a 50-50 proposition.
What I do know for sure is that if you switch to a domain name, you will loose your current ranking until you show Google that you're in it for the long haul.
As for forwarding the url ... typically I would say that you'd absolutely get punished by Google for doing that. However, since it's their url you're forwarding ... it's anyone's guess. Are you a gambler?
Maybe some of the other SEO bloggers can chime in on this one too. Lots of experienced people here.
