Recommend a tripod for my needs?

I have a nikon d3100 dslr- the heaviest lens I use is a nikkor 55-300 mm. I'm looking for a tripod that is pretty light and compact but extends to a good height (at least 130 cm). I've been told to look for ones with separate ball heads… Also one that quickly snaps into position… What do you suggest?

I would suggest Manfrotto 7302YB M-Y Tripod with Ball. It is a solid and stable compact tripod.
Maximum Height 56.7"/144 cm. Max load 7.7 lbs./3.5 kg.

Tripod is a buy once product. Get the right one and it will last a lifefime, even if you get heavier cameras and lenses. Additionally it's useful to know your height, it's best to get a tripod that is suited to your height, and also your budget so we can recommend a specific product.

As a minimum I'd say you need a Manfrotto 190 series tripod, The only 4 section tripod is the 190CXPRO4, get the 460MG head for the lightest weight package. If you want a better tripod, you should look at what Gitzo have to offer. Gitzo's traveller and mountaineer ranges have the most interesting products, the Series 1 4 sec. Travelers are quite interesting, only 1kg, but gives you 7kg in support.

You can consider Joby GP3 Gorillapod SLR-Zoom Flexible Tripod For The Nikon D3100, P7000 Digital SLR Cameras

Flexible tripod designed for digital SLRs or camcorders weighing up to 6.6 pounds (3 kilograms)
Fits into your purse backpack or roomy jacket pocket
Innovative segmented leg design to ensure secure mounting
Standard universal 1/4-20 screw for attaching your camera to the tripod mount (or use your own tripod head); 1/4-to-3/8-inch adapter included
Lets everyone get into self-timer shots