sounds like you have a couple issues to work out.
For the charging system, if you put a volt meter across the battery it should read around 12V with the engine off. When you start the bike it should come up higher: 12.5... 12.7.... 13.0 V esp if you rev the engine a bit.
If it does not come up you have a problem with the charging system.
If it does come up, but your battery keeps going dead, your battery is old and expired.
Ditto Lesblank on washing the engine down good, then seeing where the oil is coming from. A common ooze spot is the valve adjustment tappet covers (o rings) or the crank case vent tube up to the air box.
If the bike is not leaving a puddle on the floor its ok to ride it, just keep an eye on the oil level.
when you start the bike pull the choke all the way out, and as soon as it starts push it back in one or two clicks. Dont let the bike sit there running on the choke, check your lights and brakes and ride off. About a half mile down the road push the choke all the way in. After about 5 miles or more you can set the idle speed if you think its low, but dont worry about the idle speed when the engine is stone cold.
These are very reliable bikes, usually when something goes wrong its a simple fix, like a 5 year old battery or simple gasket replacements.