Transferring the domain to another registrar/hosting

Hi! 🙂
Today’s question:
Currently my website running WP 3.2.1 has a registrar A and a hosting A. I started the process to transfer the domain to a new registrar/hosting. Now the problem is: the previous registrar doesn’t allow me to manage DNS/NS (the new one yes).
I moved all my files to the new hosting and managed to have it working setting up the imported database with the new settings, etc.
The problem is that to do these changes and see if my imported website worked on the new hosting, I used a temporary address, for example: nameofwebsite.temporary.com (while the “original” domain is domain.com).

The conclusion is: when the transfer will be completed, users that type domain.com will be redirected to nameofwebsite.temporary.com. And until the day of the transfer I have to copy all the posts added to the domain.com website and immediatly after the transfer I have to change the new WP installation url back to domain.com

It’s a bit messy… is there another way to solve this problem? Maybe redirecting by now domain.com to nameofwebsite.temporary.com (it’s a bit ugly anyway!)? I tried also to edit the wp-config.php file of the current hosting setting the database parameters of the new hosting, but it doesn’t work… 🙁

Thanks in advance guys! 😉