Add PayPal credit card payment facility to existing website - take 2

I am operating a freelance business via my website. I would like to start accepting credit card payments through my PayPal business accounts. PayPal offers several options for this but I don't have to time to research them in detail and I also have only limited experience in web site design. I need one "Payment by credit card" link inserted to my website that my clients can use once they have received an invoice. This link needs to utilise one of the options offered by PayPal. I am located in Australia. I will provide the required password to my website. You will need to have experience in setting up such a payment system and have web design experience.