Othen

Hi,
Do you have the ability to check the charging voltage (you just need a multi-meter - perhaps a friend or neighbour has one you could borrow)? That would be a good place to start, it needs to be around 14V (certainly over 13.3V) otherwise the battery will not be charging - this is a really easy check.
If that is okay check the resistance to earth (well, actually the negative return path from the terminal) - again this is a really easy thing to do that will just take a moment.
If those are okay then make sure the tickover speed is high enough (mine was set at 1000 RPM when I bought it, it was only charging at 12.7V at that speed) - it should be 1200-1500 RPM, that might solve the lumpy running as well.
Those things are the easiest and cheapest to check, and may well solve the problem. If they don't work and you are not comfortable with fixing bikes then I suspect someone from this site who knows your area will recommend a mechanic soon.

Good fortune.

Alan