Head over to Humble Store to get it.
Just in time before GTA V release, you can get all Grand Theft Auto games (GTA IV Complete, GTA 3, GTA Vice City, GTA San Andreas)! This offer seems to be USA only but I bet if you manage to buy it in Europe somehow it will work jus fine on Steam. Check it out on newegg!
Mafia II Complete Pack is now on sale on GMG. The game goes for a little more than $9 and is Steam redeemable. I always liked the game even though it was not entirely open world like Grand Theft Auto games. Anyway if you like mobster games you have to play this. Use the coupon: GMG20-GGN5D-FC3NA.