What happens when you source your ~/.bashrc? Tye source ~/.bashrc
and see if your prompt changes to the one you specified. If so your problem is that it's just not executed when you log in.
Make sure your .bashrc is sourced (executed) from your ~/.bash_profile. In the latter you should have lines approximately like these:
if [ -e ~/.bashrc ]
This will make the commands in your .bashrc always are executed.