You can only do one online return on each account. You must start a new account and pay again for your daughter's return. If it is very simple, you could use the Free Edition for her.
The tab at the top of the web TurboTax web site which says Products and Pricing is where you can choose between the online and download products. As you apparently know, you can prepare and efile up to 5 federal returns with the purchase of one download product.
