Create an online invoice

I run an e-commerce website renting holiday apartments. Tourists browse the apartments available, then book and pay online through SagePay.
Sometimes they want several apartments and as there's no basket software I have to do the transaction manually and take credit card details over the phone.
Rather than use the phone, I am sometimes able to use PayPal and send them a Payment Request, but not everyone has a PayPal account and it doesnt look very professional anyway.
I need a web programmer/designer to design me a form (or online invoice) that I can use. I would fill out the appropriate information, add the amount of money the clients needs to pay and then send it to the client so that they can enter their card details and then click to send the money to my SagePay account.
The form needs to be linked into SagePay.
I received such an invlice yesterday and have printed it, scanned and attached it for your information.