Hi there. I have the same problem but I discovered that nVidia did something wrong with their latest drivers so all you have to do is wait. I have a BTX 295 and also get 20 ~ 30 fps in Dalaran so don't worry about that. I do get like 80 fps while in any Ulduar boss encounter.
About the latency problems... don't worry too much. Blizzard has announced that their ISP has problems and that they are working on them. Also, you might want to try
WoW Tunnels - Reduce Lag, The Easy Way.. Is not free but is VERY chep and it works. I'm in South America and got down to 200ms from a normal of 350ms or more. What node to select from the list... well, it depends on YOUR ISP. Just do a ping -t to each of those servers and go for the lowest one.
Cheers,