There are a number of low end balls that will be great starters and still have use once you progress past the starter point... Storms's Hit line, Ebonite Tornado, Columbia Scout, Brunswick Power Groove are all great starters.
Also, so to a proshop for right now -- you need to have the weight checked since you are all over the place with a 16# and a 12#. Your proshop guy should not talk you into a mid or higher-end ball, but if he does know that those listed are all you really need right now. Developing a good relationship with your proshop guy is always helpful. Later, if you want to try different types of balls, you can get some great used ones from the people here. I've gotten 3-4 myself just to try out different brands.
As for the drilling, fingertip is the way to go if you want to elevate you game and it really is not that hard to get used to. I did it after only 3 months of bowling.The drilling pattern will probably be very basic like a label drilling or a label leverage. No need to experiment with different drilling patterns until you understand the basics.
Most of all, have fun. Get a few lessons if you can. Ask the proshop guy. Watch good bowlers to see things like different ways to hold a ball, the arm swing, the approach steps, the position of the release, maintaining balance,etc. Too many people just watch the ball... the ball goes the way you release it.
