It looks like the closest premium collection store is in Exton.
LIONVILLE SHOPPING CTR.
162 EAGLEVIEW BLVD.
EXTON, PA 19341-0000
It maybe just as easy to pickup something at the previously recommended Chestnut st store while you are downtown though.
There is also an option to order on line and pick up at the local PLCB store. I've never tried doing it though.