I see the following outlet from this situation (this is not complete solution - but required part of problem decision process):
- Allocate dedicated automation functional testing team (quite possible, it's necessary to partly put this team work cost into the project price). Why separate team? To rear an automation tester from every functional tester is expensive, long and ineffective (and sometimes is almost impossible).
- Tester should write a testing plan (e.g., Minimal acceptance test plan) for the automation testers.
- Tester should know how to execute automated tests and to analyze their results.
- Well-qualified team of automation testers, services of which could be sold and which perform automation tasks quick and with high quality.
- The minimal set of regressive tests, that could be run in a nightly manner, for example, for every build. It should decrease the number of overlooked errors.
- Increase of time, that tester spends testing the complex and/or new functionality.
- Quality growth