Your biggest gains will come from faster glass and, if you can rent one, a better high-ISO body.

• A fast prime or zoom helps a lot. Moving from a kit lens at the long end (around f/5.6) to f/1.8 or f/1.4 is several stops more light, which can mean faster shutter speeds or lower ISO.
• A full-frame body can give noticeably better high-ISO performance than the D7000, roughly a couple of stops.
• Use available light strategically: instead of standing in the darkest area, shoot near streetlights or building light and let the action come into those brighter zones.
• If you can’t use a tripod, a monopod can still help, and so can bracing yourself or the camera against a wall, fence, or other solid object.
• Consider black-and-white. Under tungsten lighting, white-balance correction can boost noise, especially in the blue channel. A monochrome conversion can hide noise and may look better artistically.

In short: rent a fast lens first, then consider a full-frame body, and work the available light rather than trying to shoot deep in the darkest spots.