This can be done in a couple steps. First, highlight the range. Go to the data tab and click "text to columns" (alt+a+e). Click fixed width, then next. On this tab, click to create a break after the first two letters, then finish. This will create two columns, of letters and numbers. Now highlight both rows and click on the "Sort" (Alt+a+ss). You can then add a level to sort by numbers after you sort the numbers. In another column, you can recreate the original string by using =text(A1&B1,0), and then paste special the values if need be. There likely is another way to do this but this is the best I can think of! Hope it helps.

Cheers,
Mike