I just got the GotY eddition (which is sweet). I know this might be a stupid question but what stats do you need to inscrease to wear heavy armour? I was looking trough perks and i cant find it.... :(

Heay armor isn't a perk of stat related skill. You can get the heavy armor training during the main quest but I believe some heavy armor can be used without it but none of those are in the standart game.

huh?

Is it an NPC that trains you? and which stats do I need to improve?

Strength carries more equip

there is also a perk that allows you to wear the heaviest armor in the game.

I usually go for the perk that lets me increase a stat (intense training), and then I get strong back 50lbs more carrying capacity, comprehension (2pts per skill book instead of one), educated (3 extra skill points per level, do this ASAP)

The one you are looking for is called power armor training. It's not a standard perk, it is learned in the game by asking a specific person near the middle-end of the game.

http://fallout.wikia.com/wiki/Fallout_3_perks

As said strength is useful as you need the extra inventory space to carry the heavy equipment but that is about it. I believe agility gets taken down while you in the armor aswell so you might want to work on that but if your a RPer then you want this penalty since it fits the armor.

You will meet this person in the later parts of the main quest, I could spoil more but when the oppertunity to get the training presents itself it will be clear enough.

as the stated above its the special skill you can  aquire in the game

an if  

you are talking about mainly power armor?

if so the main stat's depend on which type of power armor you intend to use:

for example:

Tesla power armor provides +10% to hit with energy weapon's, so  a higher perception will allow you to hit target's at longer ranges with energy weapons like if you use the vats system.

but

say you use the Brotherhood of steel power armor

it provides you with better strength enhancement so it would allow you to carry more weight, and do better HTH combat damage.

there is quite a number of power armor types

Hellfire power armor is currently what my character uses it has great  resistance to flame weapon attacks

you do need strength to carry it though. But there are ways around leveling your strength.

yup...a certain enhancement to your bones!,

when i saw that was in there i just about flipped...just about you could almost make wolverine from the x-men comic's in fallout 

that game is pretty addictive, so far i have collected 15 suits of power armor...i guess you could say Im on a "power armor kick"

that and doing 43pts of damage with a plasma rifle to the head in the vats system to those super mutants...., i guess that could be that Im on a  

"super mutant head removal kick" also

I know strenght allows you to carry more items but i have pretty high stats in strenght and when i try to equip the enclave armor its keeps telling me that i lack training in Heavy armor.... so im wondering if there is an NPC or something that trains you for it....