How to pay for something you bought on eBay?

I have no idea how to do it. I was lookin for a cover for my blackberry, I picked one out and when it came to the payment part I couldn't figure it out. I thought a laser card would work but it wouldn't. Then I accidently clicked on something and now ice bought it but I have to send them a cheque?how can I do this?I don't even have a cheque book?can I go into my bank and ask them to transfer money from my account to the name of the company they told me to make the cheque payable to?please help