If you want a lot of Vitamin C you should eat: Red pepper, Kiwifruit, Broccoli, Redcurrant, Brussels sprout, Lychee's (just a few examples)... they have more than twice as much vitamin C (Red Pepper more than 3 times...) as lemons... Or if you really want a lot of vitamin C... Acerolas have about 40 times as much Vitamin C as lemons.
Edit: Yep, tea is a good idea, especially made out of ginger.Just put a few pieces of fresh ginger into hot water and wait a few minutes.