Replacing the Arduino voltage regulator
Why do you need to change over to a 7805? If you're gonna be bending pins up and using jumper wires, you're cruisin' for a bruisin'. A quick look at the data sheets leads me to believe there is no good reason to switch, other than the possibility that this is all you've got on hand?

If it must be done, here's how I'd do it: bend the large ground tab so that the LDO will sit at a large incline off the plane of the board. Tack it on, then solder your jumper wires from the pads to the appropriate connections. 

I do not recommend doing this, just sample a replacement part. You'll get it for free, and have the satisfaction of a job well done.