Hi
If you will be doing this fairly regularly you can ask your NAV partner to write you a dataport / XML CSV Port that you can reuse
If this is a once off you can drill down on the balance on any of your GL accounts, remove all the filters then apply filters on the accounts / dates as required,
In the RTC you can press "Control + E" and NAV will automatically drop it into Excel
In the Classic Client you can select the records by clicking the top right block to select everything (Like you would in Excel) then copy and paste it into Excel
The transfer might take a while if it is a lot of records, so if it looks like it is not responding just leave it until it finishes (Within reason)
Cheers
Nev