How well can I run Dolphin?

[Shonumi]

Your CPU won't be fast enough for either game, although your GPU will do fine for 3x IR + various amounts of AA in most games. Ideally, you'll need thoroughly overclocked Sandy Bridge/Ivy Bridge/Haswell CPU for either game. The Last Story is a very demanding game overall. Twilight Princess may require LLE audio (HLE audio "works" sometimes for some people) and even with HLE audio, Hyrule Field gets very demanding as the game progresses. Your current CPU may handle parts of LoZ:TP outside Hyrule field decently, however, but I imagine you'll still get slowdowns.