You can't generalise all Muslim girls to say whether they would or would not date a non-Muslim. I'm Muslim (albeit not practicing) and I would. Having said that, many of my Muslim friends wouldn't even consider it. Some would but would also expect him/her to covert in the long-run. Some can understand Atheists, some can't. Some have imposing families, some don't. Personally, I'd probably be more likely to get long with an Atheist partner than a practicing Muslim partner, and my parents are the 'it's your life' type so they wouldn't be much of a problem, but that's just me.
You realise 'Muslim girls' are people right? People from different countries, different cities, different cultures, different parents, different friends?