There's no need to replace the axle. Assuming it's the proper axle for 126mm OLD spacing, and therefore about 137mm long, it can comfortably accommodate another 2mm of spacing (unless 2mm is mover from left to right side, so OLD remains 126mm).

So, it's about a washer being moved or added, and redishing the wheel when done. Total cost a buck or so, plus a few minutes of your time.

BTW - keep in mind that the next standard axle length is 4mm longer (for 130mm) and could easily be too long.