Hi, I have found myself in this situation too. I know and feel your pain. Our 325i has done a similar distance and I am gatvol with all the things that keep breaking. I had to charge the battery over the weekend when it went dead. The car is back on the road but I don't have a good feeling about that battery's ability to hold a charge.
It is a tough one. You will find that the car is not worth very much, especially if there is some mechanical malady. It is better to fix and then sell. Probably. But then one gets the feeling that the car now owes you money and it has to pay you back with a few more months/years of service. Unfortunately, an old E46 may just find another way to get into your wallet while serving out that sentence. Ask me. I have been there.
If you do sell you will not get something else that is better for the same money. In fact, you might get someone else's problem car. So you can stick with the devil you know.
On the other hand, this may just be the latest in a long list of repairs already done. In that case one feels that the time has come to cut your losses and move on. Just know that you will have to cough up to get what you are used to. An E46 is a nice car when everything works and a Golf or a Corolla will just not do. Anyway, there is no such thing as a cheap Corolla, it seems. If it is still running, a Corolla is worth serious money. Go figure.