I have just started SLR photography and never understood all the f numbers and digits well. I would like to buy a decent SLR under $350 with a set of lenses so that i can do

+ pictures of Fall trees , lakes arnd my place
+ portraits and model portfolio of my friends
+ sunsets , sunrises etc
+ Snow Fall etc..

They are for my personal collection , so i do not need pro quality .

i have figured out i get a n75 for 220 $ with 28-80 af f3.3 - 5.6 G lense and for another 130 $ i get 70-300 mm f4.5 - 5.6 G.

The question is ?

1. Do i need a 70-300 mm lens for above purposes ? what use is a 70-300mm lens?
2. where do i get info abt what all these numbers i never cudnt understand them well.any urls?
3. This is my first slr buy ,Is N75 with above combo the right choice?(my budget is 400 $).am i spending my hard earned money stupidly?


sorry for bein a pest , but i wud appreciate any response ..

Thanks in Advance,