It's an Astra... My HONEST advice (Even though it's a run about) GET RID OF IT!
My mother just had all matter of issues with hers. We finally got everything fixed, and before driving it any more (In case it broke again) went and traded it in...
Different troubles the car had over 18 months, BHG, snapped a timing belt, was over heating (With the whole cooling system replaced), in that time it also had the radiator explode, a hose that looked in perfectly fine condition burst, as well as a number of other problems... As well as all of the oil leaks you've been mentioning... These cars for some reason, once they start breaking, they keep breaking.
GET RID OF IT!