First of all - Do not lubricate your brake pads or you will not be able to stop!! Brakes are the most important thing on a bike. www.youtube.com/watch?v=7oPxuyQ7YKI
You will need to buy a some allen keys - these are awesome (and pretty lol). www.flickriver.com/photos/soggy-semolina/t
You can tighten the quick release seatpost clamp by opening the handle and turning it in a clockwise direction, it should tighten up, then close. If that doesn't work you may have the wrong sized clamp for the seatpost.
You can buy a new longer seatpost at any good bike shop.
Google is an awesome resource for bike maintenance. There are thousands of videos online that show you how to fix things.
You can fix almost anything using videos online. I fixed my gas stove and replaced the headlight bulbs in my car this year with the help of a video I watched on the net!