Still new to brewing question for ingredient kit

[Atomic]

I have made 2 batches so far. My first being ok but the second i made after reading more and understanding more this batch turned out great but my ABV was a little lower then the packaged ingredients said. My question now being I purchased a ingredient kit from True Brew it is a belgian ale what do i need to do to kick up the ABV? could i purchase any additional ingredients to spike it up? The package says i could get 6+%. I would like to get it close to 7 or above. Is this possible.

 

[Atomic]

Unhopped Light Malt Extract (1 can)
Extra Light Dried Malt Extract (1 lb)
Light Dried Malt Extract (1 lb)
Wheat Dried Malt Extract (1 lb)
Belgian Candy Sugar (1 lb)
Pale Grain Malt (.375 lb)
Grain Steeping Bag
Northern Brewer Hop Pellets (1 oz)
Styrian Goldings Hop Pellets (1 oz)
Czech Saaz Hop Pellets (1 oz)
Fermentis T-58 Ale Yeast (1 pack)
Priming Sugar (5 oz)
Bottle Caps
Instructions