Hi Adorabowe.
I just did some quick math so it's not perfect. You will need at least another jelly roll and double the other fabrics. You will need to make about 2 1/2 times everything. Is there a quilt shop within reasonable distance where you can get some help? Your cream squares and units will be 6 1/2 inches unfinished, or 6 inches when assembled. If you make it so you can use a king size flat sheet for the backing you will have a nice size for a "bedspread" on a king size bed.
If you have not purchased the pattern, please do so before you start. The price is minimal for the information you will learn from it.