oh my God! I’ve been online today long enough for someone to go out and get a job! 
I’d say a thank you card will be enough. You’ll have plenty of occasions to buy gifts when he/she’s actually your boss. Congrats, btw!
“There’s a snake in my boot!”
Yes, card, no gift, says I. It looks too much like a bribe 
I’m delighted to hear it went well, and hope you get the good news really soon!
Catrandom
Just a thought: A formalish thank-you letter might be better than a card; more formal and all.
Catrandom
Catrandom is right, keep it professional so you don’t come across as a weird slobbery stalker type. 
“There’s a snake in my boot!”
I would hold off on the gift as well. The thank you letter, though, sounds swell.
Nothing is so bad that it can’t get worse.
Alllllllllrightythen!
::running off to write the letter::