Simple Led driver (Stepup and booster)

Hi,

I have read your web page and find it very informative.

I am a noob on electronics.

Are you able to advice me on a high power led drivers?

I am trying to build a high power torch.

Plan:
3 X K2 3W (input 4.5-5V each) Leds in series or 4 X K2 3W Leds 2 in series connected in 2 rows (parellel).

Power by 2 X 1.5V AAA Alkeline batteris in series or maybe 4 X 1.5V batteries 2 in series connected 2 rows (parellel). Anyway that can power the Leds for 2hrs min.

Do you have a simple circuit which the parts can be easily get from any electronic shop?

Thanks a lot.
WH Ng