It's generally not valid to use a country or region nearby. The weather data used should reflect the actually climate. For example, Palm Springs and Santa Monica (California) are only 100 miles apart, but it would not be correct to use the weather data for one on a project located in the other, as the climate is very different (desert vs. seacoast)
I'm not sure what format weather data HAP uses, but I imagine it is the same source info as other programs.
DOE has a complete listing of weather files for downloading. Chances are whatever you need is available there. They are often available in multiple formats.
http://apps1.eere.energy.gov/buildings/energyplus/cfm/weather_data.cfm