How do i copy a sheet from one workbook to another using VB

i have a workbook that i keep data from an exported spreadsheet named Export
The sheet i copy to is name BillingData.

i have been manually coping the data and over writing the old data, then i
just manually look at it an any data that has changed, i highlight it "yellow"

well this was OK when it was only 40 lines, but now i have to do it for 5K
lines. so i need to figure a VB code that will import it and check it for
changes. This seemed simple at first but is now way over my head.

Are there any suggestions on how i can do this.