wordpress.com to www.ads-software.com — domain mapping confusion

I’ve recently decided to make the move from wp.com to wp.org. I signed up with a host (bluehost) and installed wp. I had domain mapping on my wp.com blog. The problem is that when I changed the nameserver to bluehost, obviously it routed everything to my new wp.org blog – but it’s not ready to be seen yet. I downloaded the old theme and it looked similar but my old widgets, etc. still need work. I wanted to find a way to work on my .org blog but still keep the .com one going, especially since with the new .org blog my plan was to do an overhaul with a brand new theme. After trying to follow directions in the support forums at wp.org I was frustrated and confused (I don’t have much technical knowledge and I think that perhaps some of the info was from BEFORE wp.com allowed all permalinks to include the mapped url). So, anyway, I changed the nameserver back to wordpress.com. That’s worked (people see my blog as they always have), but now I can’t login to my wp.org because the domain is the same as the wp.com and it takes me to THAT login each time. HELP!?!?