2 Spaces Required Between Sentences

OS 10.4.11  
Ibook G4
1.5 GB Ram
Word 2004

Hi,

My grammar settings are for 2 spaces required between sentences.  I am
running  the spell and grammar check on a long do***ent which is full of
one
space between sentences.  The Grammar checker points each one out and I
change it.  It's time consuming and boring.

My question is: how can I do a Find & Replace, and change those errors all
at once?  I've tried various combinations in F&R, but I can't get it
right.

Thanks,  Rafael