Depending on how bad it is, I'd consider getting someone in to correct it initially, then maintain it yourself with a DA and finishing polish to remove light swirling (which is inevitable) and other scuffs, over time.
I struggle to use a DA now, they vibrate far too much and take too long to correct paint, but they are an ideal first step for a beginner to allow you to understand the concept of different polishes and pads, and how they respond differently to different paints and panel, for example.
Rotaries are not always heavier too, mine is under 2KG, but some of the cheaper ones (like Silverline, Kestrel etc) are pretty beastly things!!
You can see the difference here (larger one is £60 Kestrel, smaller one is £200 Chicago Pneumatic)
As with anything, you get what you pay for
