Are you talking about hobby or business? For any form of business I'd agree to get the best tools right away instead of going step by step. But for a hobby with the occasional usage as you describe it? If you have defined your budget then stay within. Many people use cameras that are much older than the usual model refresh cycle in DSLR market - without talking about 'lost money' and what not.So my problem is that i like to have my own stuff, meaning personally, and when i go into a hobby, i tend to want to have the best so as to not waste time building up from the beginning and most likely losing more money. So what i wan to enquire is that, is it a good idea for me to purchase a Canon 7D at this stage?
Next: if you were a hobby cook, what would be better in order to achieve best results: getting a brand new kitchen and equipment for 6-digit numbers (I know, one can spend also more) or finding a master cook who is giving classes during which you finally learn what tools are needed and in which quality level?
Stick to the 500D, maybe buy over from your brother if he's not into photography any longer. Shoot more, get classes, join outings, get experiences. Learn about light and how to work with it. Many members here have presented beautiful pictures taken with entry level cameras. Some have learned the hard way that a new camera doesn't mean the pictures come out at "Wow" level automatically.