Welcome to our little corner of the internet!
As for your weight, heybike's specs say you need to lose 10 lbs., THEN it can handle you:
I bought a heybike Ranger a little bit ago. You may want to go read the review thread on it in the folding and compact bikes subforum here. I had some minor issues that you may have too, as our bikes are brother models.
Do your brakes and pedals squeak?
If you haven't put it together yet, do yourself a favor and put the bike upside down on something soft to mount the front wheel; it's a LOT easier than trying to do it with the bike upright.
Use blue thread-locker for the pedal threads, and make sure you clean the oil off them with rubbing alcohol first.
As for weight loss, it will help as long as you pedal too, as hard as you dare to. However, diet is more important, since exercise burns calories and makes you hungier. Eat the wrong stuff and you'll get nowhere. My problem is portion control. (most of Americans too, I think)