Though you may want to consider (þis) líf is lǽne. A version of this crops up a few times in Old English poetry. Lǽne means transitory or temporary.
As for the second half, I've got cræft is undéadlic, though I'd like to have another look at 'talent'. Cræft means art, skill, cunning. Although, I would say it isn't really immortal. The products of talent can attain immortality, I suppose. Is that what you're getting at?
I'll have another look and see if cræft really is the most suitable word.
For an authentic looking tattoo, check out a font called Beowulf. It kind of looks like the font used in the top left hand corner of this page and is based on Old English manuscripts. I use the accents to mark vowel or diphthong length. The pre conquest English used accents but they were very inconsistent, and scholars haven't quite worked out what they're for. For extra authenticity just leave off the accents, but they look good, I think.