Well, at least you're being honest. If this is your first ever TBS, welcome to the genre! I actually started my computer gaming career on TBS games back in 1992 with the original Master of Orion, so I'm not entirely sure how to guide you into this game.
It's different than most of the other games it sounds like you've played. You have to get into the proper mindset first. You're not the pilot of a single ship or the commander of a single force. You are responsible for the fate of your entire civilization (at least in the sector you are playing in). Once you take that to heart, it should be easier to see where the draw is. GalCiv2 has the "one more turn" syndrome in spades, but you have to play for a while to get into it.
As far as the graphics go, I think that may be your system. I find the graphics to be pretty good. Not the top-of-the-line, but it's not meant to be. Also, you'll be glad to know that at least as of the latest Dark Avatar expansion pack beta, you can zoom in and out of the Tech Tree to get a larger picture of it. That may have been added by 1.04X but I really can't remember. And also, that's another thing -- if you haven't done so yet, update your game to the latest retail build. You could call it a "patch" but that's inaccurate -- there's nothing wrong with the game as you buy it from retail, but the 1.04X update contains many wonderful additions developed by the fans and developers after the game was released.
As far as hitting the turn button goes, you will be doing that quite a bit. It is a turn-based game after all.

Seriously though, I think you should try to go ahead and up the settings. If you are playing on Cakewalk on tiny galaxies, there won't be much to do. Try making a Medium or Large galaxy and put the AI opponents on a harder setting. I think you'll see that things get much more tough and interesting as you do this. You'll have to manage trade routes, use diplomacy to make tech trades and keep the other civs off your back and do all sorts of things besides just fighting. Give that a try and feel free to post again if you don't find yourself being sucked in.