It would help if your goals were more specific - as they stand they aren't measurable, so it's hard to say how you might best use a power meter to achieve them.
i'd think about something like
1) reach target weight if XXXlbs by yy/zz date
2) complete local loop in xx mins
3) could be the same as 2), but you get the drift
A power meter will help you get a clearer handle on your current performance, identify areas where you can improve and help you train to address your weaker areas. As others have said before, just having power numbers on your computer screen has no magic performance enhancing effect.
BTW riding with other cyclists who are stronger than you can be a great way to improve fitness and motivation without the $ and hand-wringing that go into buying a power meter. Good luck!