PayPal collects my customers' addresses, but I need an easy way to integrate them into my CRM.
Old answer here, but try using this PayPal to Highrise Zap.
It'll let you create contacts in Highrise or add notes to existing contacts when they buy something from you in PayPal.
Disclosure: I run Zapier, but this is what I'd use even if I didn't. :)
It looks like you need to get a CSV of your contacts to import them into Highrise:
It appears that paypal supports CSV export:
which has step-by-step instructions on how to export the details.