Soda noob question

Just attempted on Friday of last week to make our first batch of soda. Attempted doing Ginger Ale using the Old Fashioned brand extract and using yeast for carbonation. The end result left a very pungent strong flavor and hardly any carbonation. We made a 2 gallon batch and followed the recipe as close as possible just doubling up the amounts used that it called for a single gallon brew. Is there any way to save it? Perhaps more yeast and/or water? We've successfully done a couple of beer batches and are feeling slightly sheepish this turned out undrinkable.

Easy break down for 1 gallon:
Half an ounce of extract
2 cups of sugar per gallon
1/4 a teaspoon yeast.

So we doubled it. Are we not waiting long enough? Regardless of the carbonation, it tastes extremely strong. Thanks for any suggestions

If you only brewed it a week ago then yes you are not waiting long enough. It will probably take a minimum of 3 weeks to properly carbonate.

What are you making it in?

My soda is carbonated usually within 24 hours, I make it directly in a 2L bottle, so it doesn't have to work too hard.