Insert a column to the right of the existing one. Select the column with the original data and go to Data>Text to Columns and select delimited tect, next and tick the delimiter as "space". This will split the first name and last name assuming that each name consists of ONLY two words. Now cut and paste the surname column to the left of the first name column.
click here and download ASAP Utilities. Install and reboot the computer. Select both columns and go to the ASAP menu select Columns/Rows and merge data. Put either a comma or a space in the first box and you have the result.
Might be a long way round but VOG™ is probably asleep by now!