A little dilemma

Over Christmas, my husband's extended family surprised us with a little mini shower. They all chipped in and got us the Britax Boulevard Clicktight carseat. After looking at reviews I realized it is one of the top rated carseats out there but it's not a carrier. So my dilemma is would you purchase an infant carrier carseat to use for 6-8 months and then switch to the Britax or return the Britax for an infant carrier carseat? This is my first and I'm not sure what I would use if I didn't have a carrier to begin with.