To register online now:
To pay NOW by PayPal or by credit card via PayPal--you don't have to have an account with them to use their service:
Click on link below, and write in the total due that you calculated above. The amount will be in Mexican pesos (and will automatically be converted to the currency in the country of your credit card when you get your bill.)
It may seem complicated, but try it. You'll like it!