This is kind of like "stone soup". Sure, it's doing something, and sure, you'll get (some kind of) cider from it, but if you only had a ...
Each thing (sometimes very little things) will make the cider better. Since you've already started, you can look at this for the NEXT batch... if this doesn't taste really good, you do it all over again, but you change just the ...
So, how big was the bottle? Two cups sugar would be right much if you were using a 16 ounce individual service size. The more sugar, the longer it will take to ferment out. Also, different sweeteners ferment as different speeds... I hear that honey takes a long time.
You DID remember to put a pin-hole in the balloon, right? No sense jerking awake some night because of the "POP!" you heard in the kitchen. But, it will be OK, because you needed to get up to mop anyway.
Yeast that was meant for ale, beer, wine, cider, whatever-drink will work better than yeast meant for bread (at least in theory), but remember, people have been using whatever yeast they could get their hands on for millenia. Bread yeast will work. Hey, some folks didn't add ANY yeast, and just used what was left on the skins of the apples, or carried in on the bugs that got crushed w/ the apples or on the sweat that fell off the horses that powered the crusher, etc. Considering what people drank for centuries, no matter WHAT you get, you'll get something.
Consider that cider is a little like golf in that you will get better results if you remember to a) keep your head down, and b) follow through... and by "follow through", I mean, if it tastes kind of rough, or tastes kind of watery or flavorless, put it in bottles, cap it, and leave it alone. for a couple months. Or more. If it's not drinkable, it still may need to age.
I haven't been successful in that last one, because I get impatient and I wanna know what it tastes like NOW! And, from what I've been told, THIS is why you make a 5 GALLON batch (5 gallons? I'll NEVER be able to drink THAT much, if it all tastes like my last batch!) Bottle that sucker and let it sit. Put it in time-out and sit it in the corner. If it is lousy, start ANOTHER batch, but keep the lousy one and just leave it mellow. By the time "the NEXT batch" gets done, the previously bottled batches will be that much smoother. And smoother. And... you get the picture.
Lots of luck, and let us know how it is.