If you wanted to give Tina a story line and it had to be romantic (WHAT? GIRL NO NEED BOY IN LIFE TO DESERVE SCREEN TIME?), then you could've easily had her pursue some complete random and she could've introduced him to the club and it could've been hilarious.
"Is he in our Glee club?"
"Is he in a rival glee club?"
"Is he on the football team?"
"Not to the best of my knowledge."
"This is discomfiting."
"We don't roll like that 'round here."
"I don't know how to feel about this."
"Is this allowed?"
"Cohen-Chang is slumming."
"This isn't how things normally work."
"How did you guys even meet?"
"Artie. This is Brett. He's been in homeroom with you every year since middle school."
"He bought like three dozen cupcakes from us during that bake sale freshman year?"
"He's in the Confederation of White Hip Hop Music Enthusiasts with you?"
"Ohhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh, yeah. Hey man, nice to meet you. Sorry you couldn't make it into the club."