valve cap for Jura Impressa 300 coffee machine

Some are in deep love with there car, bike or whatever. I really depend on my coffee machine. It's soon 20 years old and an entire part of my day. It's not the first time I required to fix it but it is becoming difficult to get spare parts.
This is the plastic cap of a valve at the infuser which was broken (probably due to the age). The spring presses to the plastic cap to reopen the valve. As it was broken it couldn't take the metal part with and the valve stayed closed.
The whole part is