It is an important part of the game, and surely your gpu is holding you back quite a bit; I'll assume a cheap upgrade isn't an option, it isn't always for everyone.
One of the options that can get overlooked is other players spell effects on hit. It isn't in the video settings, it is in the combat part (I think). That way you don't have 40 mage fire spell effects exploding on the boss at once, stuff like that. Removing any other things, like nameplates, health bars, etc. Maybe turn of reverb in the audio?
try to run in fullscreen. turn off aero and anything else that uses resources. No open browsers, etc.
Do you use a particular anti-virus, anti-malware, or are there any other programs running in background you can turn off (including music apps)? If you aren't browsing or opening any other files, you can shut down any anti-virus/malware/etc programs while running the game. Be extremely thorough. Using a program like CCleaner can show you what is running at start up and stop it ... things like updaters (adobe, flash, java, and google are really bad about this), other things like widgets, steam, launchers, boosters, desktop crap (bing desktop came with a windows update I think), itunes/quicktime/bonjour, etc.
Eliminating as many background processes as possible can only help.
No AA/AS. No shadows. If you can run WoW, you should be able to run this game.
Tera has a different combat style and look. Fencers says it works great on less than optimal machines, it always ran well for me, minus a few issues here and there that could've been anything because they weren't persistent and didn't happen the last time I played. It is a great F2P model.
The main thing holding you back, would be the number of cores on that gpu (48), by example, a 560 has about 9x that at a slightly faster clock speed. The game runs on a single core, and 2.6 GHz isn't the fastest, but isn't that bad either ... I still don't see your hardware restricting min settings with low quality render ticked ... it just isn't -that- bad.
You could technically run the game at the next lower resolution; even though you aren't at the levels a lot of us run, less pixels to create = less load.
publisher aeria games does a lot of f2p mmo type stuff ... some have fan service female characters, some are jrpg style. As much as people use the expression; there really isn't a lot of 'wow clones' out there. It is just a wow fanboy term used to bash any competition on the market for lack of knowledge or care to learn (as any fanboyism is; just like the console bickering in the past).
You could try to get into FFXIV beta and see if that can run on your system. It is also available (in beta as well) on the PS3 if you have one, same servers, same toons (you can play on your PC, then move to the console in another room and continue).
LotRO? Never played it, but it is f2p as far as I know.