Here's a breakdown:
* ਮੈਨੂੰ (meinnu) - to me
* ਸਿਰਫ (sirf) - only
* ਇਹ (eh) - this
* ਪਤਾ ਹੈ (pata hai) - know
You can also say ਮੈਨੂੰ ਇਹੋ ਹੀ ਪਤਾ ਹੈ (meinnu ehho hi pata hai) which means "This is all I know."
It's important to note that Punjabi, like many languages, can have different ways of expressing the same meaning depending on context and nuance. So while this is a direct translation, it might not always be the most natural-sounding way to say it in everyday conversation.