Enabling Shipping

Site URL: http://www.silentseasonmusic.com

Hello,

I am setting up the shipping details for my store on SquareSpace and need guidance.

We're a rock band selling physical cds and t-shirts and receive many orders from the U.S. and internationally.

1) Understanding SquareSpace only calculates rates for the U.S., can I use the 'USPS Real-Time Fates' functionality along with the weight or flat-rate feature for all other countries?

I'm trying to get a sense on how businesses handle shipping for both domestic and international orders?

Thanks,
David