I've never heard of a mic with a "zoom lens" control!
The directional response pattern is either:
Omnidirectional: you probably don't want this for this application.
Cardioid: sensitive at the front, null at the back, pick up a fair amount at the sides, or
Hypercardioid: very directional - sensitive at the front, fairly insensitive at the sides, with a null at about 120 degrees, and some pickup directly behind.

Really, to keep the background down you need to get close to the source.

Laptops: most have a mic input which is useless for serious recording: mono and noisy. They often don't have a line input but if they do you are in luck and can connect a preamp to that; otherwise the USB audio interface is a good way - something like the M-Audio Mobile Pre USB. Two mic channels with XLRs and 48v Phantom power, a pair of condenser mics (Behringer C2, Rode NT5, Neumann KM184, Schoeps MK41 in dramatically increasing order of cost, for example) and away you go.
And Audacity, for software.

Anahata