Hi Phil(etc),
At first I assumed you were simply transposing the accomanying chords from the key of "C" into "G". For this job I find a transposing wheel is a big help, and makes it quite straightforward.
If you are looking at individual notes within the chords or, perhaps, the notes which make up the melody line, then you are likely to encounter various sharps and flats.
The sheet music you have posted is too small for me to read, but the arrangement of this song that I play (first line only) in "C" goes:-
(G7) I'm gonna C sit right CM7 down and C6 write my G7 self a CM7 letter
In the key of "G" the corresponding chords would be (D7) G GM7 G6 D7 GM7
I'd never tried it in "G" - it sounds really nice, and is easy to play - but too low for my voice!
Hope this helps,
John Colter