where would be a good place to pick up a test kit, and do i test the water or soil?
You can get a meter or water drop test kit at any growing/hydroponics store, or you can order it online. You could probably get pH stuff at an aquarium shop too. The little water test drops are less than $10.
Here are some for $5.50, and $5 shipping:
http://www.amazon.com/General-Hydroponics-pH-Test-Kit/dp/B000BT32UA
You should just go with buying a water pH meter, or the test drops. If you have a lot of money to spend, you can buy an expensive soil tester. If you buy one of the cheap soil testers, the readings will not be accurate enough to base anything off of, so don't waste your money on them.
With a water tester you can test your water before you give it to them, and if you test the runoff water that comes out of the drainholes in your pot you can get a rough estimate of the soil pH. It's not as good a reading as a real good soil tester would give you, but it is usually enough to determine if the soil is too acidic or too basic.