To the immediate right of the end of your last column, at the first row, type the following:
=A1 & "-" & B1
Go one column over to the right and type this:
=A2 & "-" & B2
Now highlight both of those new cells that you just typed, and grab the little autofill box in the lower right corner of your selected cells, and drag over until your new area is the same width as the original row.
Now, highlight the entire new section you've just created, and drag it down to the bottom of your data area.
Highlight the whole block of new data, hit Ctrl-C, and then right click somwhere and choose "Paste Special". In the dialog that appears, choose "Values", and hit "OK". Now you can move this new block anywhere you want without regard to other cells.
Finally, you will need to delete every other row of your newly pasted data, beginning with the second row.