Need help. Is Gods and Kings worth it? (can't afford much but love Civ)

Hello! I've been researching around and doing some heavy decision making but still can't decide if the DLC is worth it. I can't really afford to buy any games but saved up for a while to get Civ 5. I loved Civ 4 but my copy broke and after a year Civ 5 was out I finally gave in to my guilty pleasure.

1. I wouldn't say I play a lot due to having to work all the time but I probably play maybe 5 or 6 hours a week.
2. Ive just been wanting some real thoughts on if it's worth the thirty dollars.
3. Is there anything I can do to make the normal Civ 5 game more fun ? Because I've played the hell out of it and am looking for something a bit new.
4. Also I'm playing on a mac (uncle gave me his when he bought a newer one) So does that take away from the experience at all? It tends to get pretty laggy around turn 300 and up. Well thanks if you can give some input! Would be greatly appreciated!