The Elder Scrolls IV- Radom questions please help

I have read few guides of both and none have got an answer i am looking for so i will ask here.
1) On enchanting weapons there is a thunder sign (how much you can use for e.g 40 fire damage) at the moment i have 0(85)
and a thunder sign next to it how do i make (85) go up so i can put more into fire damage etc?

2)Items in oblivion have say 2800 charges and 44 uses but when i make a weapon it has 1600 charge and 21 uses is there away to make
my uses of the weapon go up? (even if it involves charges going up ie gems?)

3) How can i get better armour/weapons to find? i am level 18 and still have full steel with a bit of dwaren and blackwood armour?
Not just better armour but get full dwaren orcish anythink?

4) If i use forty magikca on weapons and i have 208 magikca but whislt wearing the armour its know 352, when i buy a spell
that requires 308 magikca will i still be able to use it even though my orignal magikca is 208 but i am wearing the armour making it 352?

Edit: I'm trying to Edit it but it keeps messing up my Post, I hope you can read it. 

1: Not sure what your trying to ask.

2: Some items have larger Charges and Uses but if it's a User created Weapon then it will only have 1600 or below Charge. Grand Soul Gems are the only High ones you can use which has a Charge of 1600. To have more Uses 
on the Weapon, lower the Damage/Effect. The lower the Damage (eg. Fire Damage) the Higher the Uses it
will have and the Higher the Damage it has the lower Uses it will have. 

3: Find better Forts, once your Level 20, you will see All the Armors, although at Level 18 you should see most
including Dwarvan. Also the Shops won't sell nice armor, only Mauraders will have the nice Armor. One time I did
see a Shop sell Dwarvan armor but it only comes on certain days I think. So find a Fort with Mauraders like Fort
Homestead south of the Imperial City, across the river.

4: The answer is Yes, you can buy a Spell that is over your Original Magicka, as long as your wearing Enchanted 
Fortify Magicka Armor you will be able to use it. To be safe I would Save the game before buying the Spell so 
you can try it out.

Well I hope I helped and that game is awsome, Enjoy! :) 

Rockmilk cave will meet all your weapon and armor needs.

North of Leyawiin, on the west side of the river, just off the road.

Keep your head down.