If you are just starting out, sometimes you get a telephone number from a girl, but it's way too short of digits for you to be calling her. Probably, the girl has simply given you her local number, not realizing that you may need her country code and perhaps city code to reach her.
If this is the case, you may try this web site: http://www.wtng.info/ It's a little technical, but it will give you most country and city exchanges for the former Soviet Union (FSU) countries. They will also let you know if you have to pad a number with additional digits to make it work. (Example, some local older numbers have 5 or 6 digits, and a newer local number may have 7. You then preface the older number with a zero or two in order to get it to fit the size of a city prefix + local number.)
So to make an overseas call, you would first start out by dialing 011 to let the phone system know you are going to make an overseas call. Next, you are going to dial the country code. Let's use 380, for Ukraine. Next, you add in the City code. We'll use 692 for Sevastopol. Finally we'll finish with the local number. Let's say it's 11-22-33. So, to call a local number (11-22-33) in Sevastopol, we'd dial 011-380-692-11-22-33. If you connect, great. If you get a wrong number, you may need to check and see if you are using the correct city code. Sevastopol also has a city code of 690. If your girl doesn't tell you which one's her city code, you may have to do a little experimenting...
Of course, direct dialing is not really the most economical way to go. You can be paying in excess of $3 a minute to talk to someone this way. Most people purchase phone cards for calling overseas or use a 10-10 or 10-15 dialaround number (an old website, http://www.10-10phonerates.com/ , has most of the dialaround rates listed, except 10-10-987). Phone cards can be purchased just about anywhere, from your checkout stand at Walmart, to specialized cards on the web. Various web purchased phone cards include MasterBell, LeanCard, Nobel, Cognidial, Tel3, and so on. I'd list their sites, but Patrick's filter would probably kick me out as a spammer. Just do a search on the web and you should probably find them easily enough.
Hope this helps...