So, my friend got me a Britax Marathon car seat that's really nice. BUT. It doesn't lift out of the car and work as a carrier. Don't I need one that does? That way I don't have to wake up baby if she sleeping when I go somewhere? I'd also like something to carry her in when I'm in a store or going to visit someone. What are your thoughts? Help!

ETA: I'm due 1/13 with first baby