Since you are a Mets fan I will use small words. And since I'm a Cubs fan I don't know any big words so we're all set.
If you are playing at regent or lower you should not be letting any AI out expand you for the available territory. Until all the territory is claimed you should not be doing much more than building settlers, workers, granaries, warriors (MP's), and archers if you build a barracks in a city dedicated to making offense.
Don't go for a great wonder until all the land is claimed. After all the land is claimed don't go for a great wonder.
Also, if you're playing at regent or below you can get away with having very few defenders. That normally means you're better able to switch production if one of the AI's gets frisky or you refuse a tribute demand.
If you feel continuing the war isn't in your best interest then sue for peace. It sounds like after ripping the AI a new one you could have gotten peace with a few cities and their techs.
Another way of getting back in the tech hunt is to do "pointy stick research". Load up and slaughter your smarty pants neighbor. When he/she's down to a few cities they'll normally give you every tech they have. BTW, you have also just crippled them from out researching you for the rest of the game.