I'd not use Crystal Reports or any other reporting tool for printing bills IF you are targeting special printers like thermals or dot matrix/impact ones. Instead, I'd try to learn the printer target language commands (ESC/POS in your case which is not hard to learn at all) and would send the raw commands to the printer by using this code
http://support.microsoft.com/kb/322091[
^]
Printing performance will be way better than using Crystal Reports or alike.