I have started to play the game as a Mage but I use my bow a lot. Anyway I have been using the same weapons all the time which is bow/ imperial sword and there getting a bit boring

Is there a shop or location where I can get some decent weapons and if its possible spells ?

When you get to Whiterun there is a hunting shop and a good blacksmith there. Also, if you improve you're Smithing skill then you will be able to craft and improve better weapons.

Train smithing. Seriously.

I made myself full Superior Dwarven Armor and a Superior Dwarven Warhammer which now has around 60-65 attack value. Smithing is nearly not 39.

Training tip: Get the warrior stone bonus, buy alot of iron ores/ingots and leather strips 1:1 ratio and then make as much iron daggers as you can and you'll be there in no-time.