2008 Ford Focus ac not getting cold but does blow air normally and heater works?

I have a 2008 ford focus and just replaced the battery about 3 wks ago (don't know if that matters or not) started the car about 3 days ago and air does not get cold..now that's in the blazing heat..i waited until night time and turned it on and noticed 2 vents get a tad cold and the other ones are warm air. I checked the coolant and it is full..i have no idea on where the frion is in the car so im not sure about that but since 2 vents are getting a little cold i figured that might be ok. Any idea on what it could be? I would be very grateful cause i have a newborn and not a lot of money to fix the issue. Thanks so much!