Script to geotarget / Freq cap ads

I need a simple script that will allow me to select which countries see an advert. For examnple if AD1 it is set to USA and United Kingdom then anyone surfing the website who is from those countries will see AD1, while people from France or Germany will automatically and seemlessly be defaulted to AD2. I also need to be able to select frequency cap. So People from The USA or UK will see AD1 for example 2 times, then after that they too will be forwarded onto AD2. I don't want anything complex, if possible just a single file to set one advert. In that file I should be able to: - Set which countries I want the ad to display to (must allow multiple choices) - Set the frequency cap - Set the path to the txt file to be included for AD1 - Set the path to the txt file to be included for AD2 as the default advert