Manuel
Here lies your problem: we cannot give you your PhD topic!!! You have to start reading the literature on whatever field you are keen on (and by the way, just saying macro or development economics is not enough as these are HUGE fields). Once you decide on a field, then go more specific (by region, theory, etc…) and start reading what's been written on this field lately. You don't need to be in a university library- the Internet could be your first place of research. Also, what's the point of contacting supervisors if you don't have a topic???? Time to do some online research/reading I'm afraid before doing anything else.
PhD Economist.