I've just discovered how to do this (sort of) so happy to help. Go into design mode via the control tool box (right click on an empty bit of the top tool bar to select Control tool box if you haven't got it). Then right click on your combobox and select properties. Go down to 'Linkedcell' and enter the cell reference where you want the Combobox selection to be outputted to, eg sheet2!A1 ? I prefer to give these cells a specific name rather than A2 etc, so it will keep up when you enter delete rows and columns. (you need to exit out of design mode to be able to select your combo box as normal)
you'll then need to link this output with the its respective code. Hmmm can't think of an easy way of doing that, but as I say I am new to this stuff - perhaps others can suggest?