TOPIC: Payment Options

Hello, two questions for DTRegister v.2.7.9a, running on Joomla v 1.5.23

I want the user to have the option to select pay later OR pay pal. Can someone please advise how this is done? Do I create a new 'pay option' somehow that enables these two functions?

ALSO

When I tested the pay pal option the site redirected just fine, however I want the redirect to go to a new window, not the parent window. What file must be adjusted in order to enable this feature?

Appreciate any help, need to go live with this in 2 days!
Thank you!