As a suggestion I would just pick up the additional URL and create a redirect - also let the Search engines know via the redirect the new domain name.

Another but less attactive alternative is to buy the domain and then ...

Create a robots.txt

User-agent: googleBOT
Disallow: /
Place in your root directory
You can also place a robots exclusion tag in the head of each page:
<meta name="googleBOT" content="NOINDEX,NOFOLLOW">

You can then manually remove all urls here:
http://services.google.com:8882/urlc...&lastcmd=login