Accept the offer without any bargains! Then keeping hunting for a better offer. Once you get the new offer, say bye-bye to the agent. That's it.
This is my philosophy. I am ready to be kicked off by the client anytime, but I am also ready to fire the agent and the client. You guys seem not to understand the rule of game. The keypoint is one word: INTEREST.
Once you get a better job, leave that agent and his client relentless.
Don't think you can add some glory to the Chinese community or you will defame Chinese programmers. Actually, the agent helps you for their own interest. The client hires you for their own interest. Once they find you are no longer useful to them, they can get rid of you without an eye-blinking!