My wife and I plan to be in Latvia (Riga area) for 3 months (Jun, Jul, Aug) this year and are searching for the best solution to have a compact/mid-size car for use in Latvia and the rest of Europe during this time.  Any experiences or recommendations re. car renting, leasing, importing from the USA or Germany, buying locally, or any other approach will be much appreciated.  I am including the possibility of buying and storing because we plan to take similar summer trips on a regular basis.

How about a nice low mileage convertible from Finland:
http://www.mat.fi/forsale_1949zis110.htm
http://www.mat.fi/carsforsale2.htm