The best way to get statistics on your games is a program called sc2gears. It analyzes your replays and gives lots of data. To get this info, do a multi-replay-analysis on all of your replays, double-click your player name to do analysis on just you, and look at "Match-up Records".
That screen is a bit confusing though. It shows all the possible ways to express your match-ups. Your race is the first one (e.g.
PvZ means you played Protoss,
ZvP means you played Zerg).
* means any, so
*vP means your total stats against Protoss and
Pv* means your total stats playing as Protoss. There is no consideration for "random".
Sounds like then you would be interested in the
sc2gears now supports a google-hosted database of all of your replays. This is basically the direct response to battle.net not showing win/loss data anymore.