Hey Yue - Would recommend adding the link to your signature so that when you comment on other threads, people have the opportunity to check out your project. Have you tried out this cross promotion? i-will-pay-2-to-your-kickstarter-project-t1511.html
Learn how to succeed on Kickstarter: here. Submit a free press release for your Kickstarter campaign here.
More perks more perks more perks! Like the idea, and you've already gained traction, so lay it on with more perks. Maybe you could allow people to pick how you draw certain images for certain prices. Just an idea.