I wouldn't call an i3 mid-range. It's low end. Or as I call it "fake quad" since it's 2 physical cores with HT. Anyhow, I think if you can find one for sale cheap enough a GTX 460 SuperClocked would be a good buy. Those are supposed to compete against 5830's and usually can be found for about the same price as the 5770's. And they never get hotter than 65C and can be used with as little as a 450W PSU. So consider it. As far as the CPU is considered, you have to figure what is going to work best with your budget and what you plan to do long term.
Example: I have a GA-p55a-ud3 motherboard. It has the 1156 socket. Great. The board supports crossfire. Great. But this board also has SATA III and USB3. That will take up some of the available PCIEx16 lanes that could be used for a second card! Not good. The 1156 chips, from what I recall, can only support up to 16 lanes on the PCIEx16 channel. In other words it can use 2 video cards in crossfire X at 8X speed, or if you have a chipset like mine, 1 video card at 8X and 1 video card at 4X (which is a waste) if I am using sata III or USB 3. So the lesson here is get one good card and stick with it if you plan to go the Intel 1156 route. They CAN do multiple GPU's. But in any configuration that enables next-gen features (USB3 and Sata III) It just doesn't have the available lanes to do so effectively.
AMD however if more forgiving, since PCIE lanes are still controlled by the northbridge (if I recall correctly). If your on a slim budget get a Phenom II X2 550 and later on try to unlock it. I like my 890GPA-UD3 for my AMD build but I've read quality has been spotty.
Hope it helped.