For 2 people, a 3 man tent is considerably more comfortable than a 2 man. Most are about 7x7. Lay out a 7x7 space on the floor and try to get 3 sleeping bags in it.
I have one of these Eureka Tetragons in 3 man that I've had for 10 years of more. It's been a very good tent and has stood up to some hard use which is surprising considering it's fairly low price. Weight is 7lb.
EUREKA TETRAGONIt also comes in a 4 man for about $20 more. It weighs about 2lb more than the 3 man but would be much better for 3 people.