The proper officially approved by VW oils that are widely available in the US are Mobil 1 0w-40 and Castrol 5w-40. Both are full synthetics. The 5w-30 will be just fine if you'd rather stick with that. It is not as critical as with a turbocharged engine. See this thread for more info:
http://newbeetle.org/forums/2-0-liter-gas/48317-what-oil-do-you-use-your-2-0-a.html
As for oil usage, you probably have a leaking o-ring between the engine block and the oil cooler. Mine was very brittle when I replaced it a couple years back. My oil use went from 2.5 quarts/5000 miles to 1.5 quarts and it rally wasn't that obvious from looking at the engine that any was leaking. The coolant needs to be drained and the hoses removed from the oil cooler in order to take it off and replace the gasket.
http://newbeetle.org/forums/2-0-liter-gas/48317-what-oil-do-you-use-your-2-0-a.html
As for oil usage, you probably have a leaking o-ring between the engine block and the oil cooler. Mine was very brittle when I replaced it a couple years back. My oil use went from 2.5 quarts/5000 miles to 1.5 quarts and it rally wasn't that obvious from looking at the engine that any was leaking. The coolant needs to be drained and the hoses removed from the oil cooler in order to take it off and replace the gasket.