how to change ‘live site’ url?

hello,

i installed wordpress 2.7.1 using a temporary numerical address eg:

https://xxx.xx.xxx.xxx/~username/blog

then i updated my nameservers to point to a domain name.

it is now resolving properly.

can anyone tell me what i need to change to make sure the site is now the domain name and not the numerical address?

for example, when i try to login to:

domainname.com/blog/wp-admin

it is redirecting to the temporary numerical address.

thank you very much!