need advice on motor oil selection

Hi..... I just got a 1996 Jetta Trek. It is being used for everyday driving. I am 1,300 miles over my oil change date (haven't had much time). It has 123,500 miles on it and I want to know what weight of oil I should use. Also, which is better: conventional oil, synthetic blend, or synthetic. I have no idea as to what it used to get. I know that I have Coastal 10W-30 in it right now. Any opinions accepted! Thank you in advance!

According to VW: If it stays above 50F use 20W50, if it stays above 14F but not above 50F use 10W40, if it stays below 14F use 5W30. Use a better quality brand, I don't like the synthetic or blends for your application & mileage.