How can I quickly earn 500 Bing Rewards credits?

I just joined Bing Rewards a while ago and now I have 276 credits and I want 500 to get a Microsoft Points card. Is there any way I can speed up this points earning process? I read that you get an additional 250 credits for downloading the bing toolbar, but I did download it just now and I still have 276 credits when I should have 526. Also, does the Microsoft points get sent to you by mail or online?