Tarte 4 day lash stain gives you eyelashes beautiful color that lasts until you take it off with oil-based eye makeup remover. It doesn't lengthen your lashes it just makes them more visible.
I would suggest Urban Decays Big Fatty Mascara
It will help fill out your lashes and even though you can get the colours from Sephora, i noticed on the Urban Decay website they have a number of colours available (and on sale I believe). Blue, green, purple take your pick.
Heres the Sephora link for you to check out the initial product.
If you want a mascara just for its color then I'd recommend trying the tokidoki Punk Lash Mascara. It's not the best in the world when it comes to lengthening your lashes, so I only use it when I want to add color. It's available in four intense, layerable colors and it has a specially engineered brush that defines every last lash with color. You can read about it here: http://sephora.com/browse/product.jhtml?id=P257106
If you want to make the color stand out even more, you can apply a white eyelash primer before applying the mascara and it will make colored mascara really stand out on your lashes. Just thought I'd give you that little tip in case you've never heard of it before.
I hope this helps you.