Keep leading zeros?

Hi!
I have been struggling with this for a few hours and have exhausted every avenue i can think of.
I have a text file with several hundred strings of text. Each string is of varying length. I wish to extract the last four numbers from each string. The numbers are separated by spaces and vary between 0 and 9999, so i cannot do a simple RIGHT function.
What i have tried is the following;
I found quite a nice macro that reverses the text in a string. I use this on each line, thereby putting the numbers i want at the start of the string, but backwards. I then use text to columns, using space as the delimiter. I then use the same reverse function as above on each of the fields i require.
THE PROBLEM!
If any of the numbers end in 0, after i reverse the string and then delimit it the zero is lost because it is treated as a leading zero. I have tried formatting the fields both before and after the delimitation, either as text fields or by adding in zeros with a custom format and nothing works.
Does anyone know of a way to keep leading zeros after a string is delimited? Any other suggestions as to how to solve my problem are more than welcome too!
Thanks,
Cj