Switching to a DVI adapter would certainly resolve your issue. As you have it now, your MBP is outputting a digital signal (DP) which then is converted to analog (VGA) and then back to digital (for display on the screen). DVI would keep the signal digital through the whole process.
As for which adapter to get, both single and dual link will work at a resolution of 1920x1200. Only above that resolution (i.e. 2560x1440) requires dual link. The type of DVI doesn't matter either, since you will only be using the digital signal rather than passing an analog signal through it, so DVI-I and DVI-D will both work the same.
In the meantime, you should be able to partially counteract the "fuzziness" you are experiencing by opening your monitor's OSD menu and auto-calibrating. This will work in most cases, although for your particular hardware loadout I'm afraid I'm not 100% sure. But it's free and worth a try.