Joomla Customization

I already have a joomla website that I created. I need help doing the following. - Want them to be able to sign up to my site - I need a sign up module (I purchased one from mambopal but they still haven't put it in my site) - I need a Paypal button and shopping cart system where people go from the calendar when they sign up for the events/ The website address is in an attached text file.