Hi, well I have a tumblr and I'm starting to make money with this account.

Now I think I'm ready for the next step: Selfhosting and independent platform. I already have the hosting. I want to create a wordpress and make it my main site of course I will keep my tumblr account.

Here is the thing:

I have a domain associated with this tumblr account , and right now is PR5. I don't know if I should change my tumblr domain and the current tumblr domain pass it to the new wordpress. Or I should keep my tumblr intact and make a new url for the new wordpress?

Can I lose the current PR or anything if I make my tumblr domain a wordpress one?

Right now all my traffic comes from tumblr, just nine percent is organic traffic. (is that low ?) I have made everything to increase my SEO (taglines, metatag, submit sitemap to google, bing, etc) but it seems that tumblr sucks for that and I always see my competence ranking better with wordpress and posting just an article a week.