Product lists and login layout problems..

Hi,

Im a newby when it comes to building websites and i've worked for hours just to figure out how to display my products. But know im stuck. I wish to display them in a precise manor but i have no clue how.
I want:

My (sub)categories to have a border from about 1.5 px.
My pictures of (sub)categories to be bigger.
My Products listed neatly beneath eachother (also with a 1.5px border around them) ( like this)
My website looks like someone stepped on it.. take a look...

BEsides this im having trouble with my login (inloggen in dutch) layout.
I dont want the picture of the keys, the text next to it and the module saying i have to login first. But i dont kno where to adjust it

I hope these are not to much questions and my apologies for my english, (it is not my native language)

Kind regards from the Netherlands

Alex