Give the context of the (mis)quote, I'd offer:
Luca, ego pater tuus sum.
In Latin, "your" is most often the adjective tuus, and thus declines with the noun it modifies. Because pater is masculine, so too would be tuus. If it were 'mother', then you'd have mater tua.
The order pater tuus is assured, though tuus pater isn't impossible. There's no reason to separate it, though, like you did. You'd only really see that in poetry, and then it's done for some purpose (either meaning or, more likely, meter).
The emphasis can change depending on what you include. I think having ego is appropriate, but different speakers will use different things and they're not necessarily wrong.
Finally, for the actual quote, this would be a great example of using immo. Note that Darth Vader actually says, "No, I am your father." In Latin, this could be rendered:
Immo ego pater tuus sum.
The immo here counters what was previously said ("He told me you killed him") and points to a correction of it.
The sum is optional, since ego is already spelled out, though I'm torn as to whether Vader would drop it. There's something to be said about the rhythms of a snappy sentence (without the sum) v. the fuller, more formal sentence (with it).