Battery not holding a charge.
I'm really new to this. Alright... I'm in the Marine Corps, and I'm at MCAGCC Twenty-Nine Palms CA, I originally live about 80-90 miles away, and I own a 1995 Nissan Altima. I have been having problems with it, recently I replaced the spark plugs, and recently it started giving me trouble, slowing down when going up hill to about 35-40 MPH, whenever taking on an extended load I suppose you could say. I can hear a leak somewhere in a valve or something, and I assume that it could be the reason, but my real problem is this, my battery is completely dead, no sounds no power locks/windows nothing. I got it jumped about and hour ago and it took a little to get it up and running, I then ran it for a short amount of time to let the battery charge up, I'd say about 10-15 minutes. I then turned it off, and attempted to start it up again. Barely any power left after about 15 seconds of it being turned off. then another 15 seconds later, still trying.... I received the same problem as before, completely and totally DEAD. If you could help me solve this problem, and maybe a hint at the other, It would be greatly appreciated, I don't make too much money and I'm about to PCS or move to another base here pretty soon and I'd like to drive my car there. Thank you. MCorps1775