I would look at AC Delco battery 78-6YR. Should fit in your car and it has 700cca which should be enough to spin that engine over.
However! Your starting issues may also be.......your starter. I just replaced the 25 year old starter in my truck this weekend. It was cranking like it was -25 out and it didn't seem like the battery had juice. I put in a new starter though because of how I treated it this winter and you would not believe the difference. It spins over very fast and fires right up.
Lastly, have you ever checked your charging system?
I love my Optima Redtop 720, holds a charge and has never let me down.
Optima Redtop Battery:
-Strongest 5 second starting burst
-Up to 2x longer life
-More than 15x the vibration resistance
-Completely spill-proof, mountable in many positions
-Faster recharging capabilities
-Optimal starting power, regardless of temperature
I was told by a female parts counter clerk once that size matters (I hope she was referring to the battery I was buying at the time) ...
I just kept telling myself she was talking about CCA's (cold cranking amps)