So i had a list of questions, and i would really appreciate it if you guys could answer it.
1. What kind of a bike should i be looking for and the cost of it ? geared/non geared/flat bars/etc...
2. What kind of tires do u guys recommend ?
3. Is buying used a bad idea ?
4. What kind of gear should i be looking out for ? Its cold and rainy, very rainy....

The cheapest used bike that fits you. When you know what you do and don't like, change/upgrade. Look for a neutral type (just like bikes...motorcycles - you start with a classic naked, not a chopper, or a sportsbike, or an enduro - start with classic and when you learn basics you see what your heart desires).
For rain and cold the only good advice is experience - shorter trips trial and error. We are all different. Generaly, active uderwear, wool, wind/rainproof layers on top, but there are 1000 variations, try and see what suits you. Again, start cheap, borrow from other friends to see what fits and suits you, THEN buy.

Bicycle is great for legs and lungs, but for track days i recommend running and lots of crouches, pushups and back strengthening excercise. Athletics training programme for say an 800 meter runner is what I'd look into, perhaps a bit of swimming. More running and stomack/back excercise, less bicycle to really be the hellcat on the track!