apply for a work permit the day you arrive.
If a work permit has been applied for before 45 days are up, then it should be relatively straightforward to obtain a temporary residence paper from the Foreigners Office to allow you to stay until the decision has been given.
If the general consensus here is that I've already broken the law then I'm definitely leaning towards having a long stay here now
I think because you went over 90 days without permission, you're illegal. But I'm hearing mumurings that they can (but this doesn't mean they will) legalise an illegal stay if there's exceptional circumstances - I know Germany has been doing this, but there's no guarantee that Poland will do the same thing.
Incidentally, it's a year's ban from Schengen, with formal notice to quit Schengen if you're caught. Some people are banned for longer, but where it's a clear cut case of overstay by a tourist, it's the standard punishment.