Should I register a new blog or upgrade?

Hi there,

I currently have a free blog registered as http://www.dawnschuck.wordpress.com.

However I’d like to change the name and upgrade to a dotcom (minus the wordpress). I have a few questions:

1) Is registering a dotcom with WordPress the same as registering with any providers (such as 123reg, for example?)

2) Should I register the new blog as a new domain under my present account, or:

3) Should I buy the new dotcom as a separate blog and transfer the content over, deleting my current blog?

4) Should I buy the dotcom through a different host and map the domain?

I would really appreciate anyone’s advice, as I’m a little overwhelmed with all the technical stuff – I do try my best but I’m quite stuck!

Thanks so much,
Dawn