[Linda Buquet]

Well I don't think anyone can give you the answer
but I can give you some thoughts and suggestions
and maybe raise some things to consider.

You do know that you can point your Blogger blog to your own domain if you wanted to do that right? (I think thats still an option?) Then you could keep publishing with the existing tools you are used to. But if you don't like the templates then I guess thats maybe not a good option.

Seems to me you should keep the existing blog going and add occasional content. You will get better rankings on Blogger than you will INITIALLY on a brand new site and you already have lots of spider food.

Starting a new site with WP would be a wise move but could take some time to set up and get used to and then time to build up some content.

If you initially keep both going so you have continued Blogger traffic and rankings while you build up the new site - then start doing all your full posts on the new WP blog - but put a content summary on the old blog that links to the new blog for awhile as you gradually transition everything over to the new site???