Thamel Java [may be cliche but thats something we got], Thamel area....bowling...keshar park has been opened[park near Java, (damn nice, no cheap crowd)], then new road ...evening ma, hog on hawkers food, :-)
yeah may be Zoo :-) not a bad idea, its been renovated!!

tell me where you are so that i can suggest you....is your gf ready to travel in public vehicle? if yes then godawari, patan darbar square(there is one restaurant ultimate good/food+ location) bhaktapur is also good....let me know what sort of place you wanna go...there are zillions places....where everybody goes and you can goto cool places (not dating place, but something cool)....

you can take her to rafting too :-).....its fun!!

P.S: based on my experience :P hope you have fun back home....

ali para jana u need vehicle...so arru cool places chan..