1) Get a better computer. More specifically, a better video card and more memory will help more than a faster processor, in my experience.
2) Exit GC2, restart it, and then load your game.
I've never seen half hour load times except on systems with integrated graphics and under 512MB of RAM-and on Gigantic maps, to boot!
3a) Yes, as you do more, and build more improvements, and take over more planets, and build more ships, the savegame gets larger-and so it takes longer to load. But a half hour is ridiculous.
