Awww normally the age that is considered to be "old" in the Muslim community is not really old, especially when it comes to women.
Since you mentioned that your apps rents will only accept a Pakistani, your best bet is having a look at dating websites. Are there any meetup groups where you live that will help you to meet fellow Atheists?
I don't think meeting Pakistani guys is that big of a problem, the bigger problem is telling them you don't believe in Islam and hence, don't want it to be part of your life once you get married. :/ If they don't share your views, which they most likely don't, they probably won't keep their mouths shut about it and the word will spread.
Thanks for offering advice though, I appreciate it!