@Yaya - The Pidgey is weak, but still shoots out a gust of wind at Nidoran (M).
@LUVTOY - The Geodude is out for the count, and the trainer has run out of Pokemon! You obtain $100, and Squirtle gains 2 experience points!
Hang on, I'm confused on your experience. You say you have 3 experience points -- but if you have 3 experience points on this level, you should be level 10 already. Assuming that, Squirtle needs one more experience point to get to level 11.
@Ukiyasan - Bulbasaur launches itself at Rattata. It's a critical hit! Rattata faints! Bulbasaur gains 1 experience point. Bulbasaur grew to level 9!
@peeup - Bulbasaur, despite its poisoning, pushes on and tackles the Nidoran. It's weak, but replies with Tackle, which sends Bulbasaur into a weak zone. (Note: Nidoran doesn't learn Poison Sting until level 8, and this is a level 5 Nidoran, so it technically shouldn't have it yet)
@zrky - Kakuna is slightly weakened by the attack, but retaliates with Harden, raising its Defense.
As for the Exp system (since I get the feeling more people than just peeup don't understand it): The exp system works like this. At level 5, one experience point will level you up to level 6. At level 6, you still only need one experience point to level up to level 7. Then at level 7 you need 2 to get up to level 8. It's a 1, 1, 2, 2, 3, 3, 4, 4, etc. pattern.
As for whose post applies, since Mewter posted first his should probably count -- but for LUVTOY, I'll stick with Skyler since Mewter didn't know where he was and Nidoran doesn't really fit in the Pewter Gym.
And yeah, as Skyler said, once the current battle ends and you move onto another one, we'll use the system in the OP.