Forget the Acai Berries as mentioned above, that's just an ad for a website. Besides, whether you get them in the Juice or Capsule form, they are both processed the same way. The berry is freeze dried into a powder for both, and when frozen the vast majority of the nutrients are destroyed.
On to your question now, it really depends on your level of motivation. As a former personal trainer of 3 years, it all comes down to whether or not you can push yourself in the gym on your own, or if you need someone there for motivation. I've seen people who were having some trouble, and then the first time they tried a trainer they began to see some great results. But my advice would be to give it a month on your own to see if you have what it takes before spending that kinda cash. Personal Trainers aren't cheap. Good Luck either way.