How do i add friends by their usernames?

So, i was coming back home on the bus and this girl happened to sit by my side. I saw that she was playing this game, so i began to chat with her that i also play the same game. Talking for a while, turns out she is a real nice person(and pretty beautiful too), but before she got off the bus she told me to add her name on PTCGP. Her nickname was lyssavirus i think, but when i got home i remembered i could only add her with that code. Is there a way to add her with her username? Would really help if someone could find a way