Internet problems, lag, dc, etc.

Hi,I have a pretty serious problem. Since Sunday, my connection to the game has been a complete trash. I get frequent lag spikes (like 1800 ms though I have a good internet connection out of the game). It usually stays at a random ms number for several seconds, while the connection freezes, then it usually ends with a disconnect. I had some problems with the ISP, but they have solved it yesterday, since then my connection (not ingame) is pretty normal. So I guess the problem is with the game. I hope you can understand my problems:D
It would be really good, if you could come up with a solution, or some advices, because the game is unplayable for me (even on default).

Thanks

Update: the problem seems to be solved, so this is no longer relevant