1986 Honda prelude 2.0 Si problems with battery and alternator.?

my little car just took a dump on me the other day as I was driving home, it went dead then started again and i had to get a jump start, so i figured the battery just died, i went and bought a new battery for it, replaced it started up fine and worked well for a day, then the other night i stoped at a 7-11 came back out and tried starting my car and bam it did not even turn over and needed another jump start.
Its a brand new battery so I am assuming maybe it has to do with the altenator, but I am not sure, and now my car is stuck in front of my place and cant even start unless i jump it, does anyone know how i can look more into this with out going to an auto zone or mechanic to get it looked at, i am currently way low on funds as well. thanks