Confusing situation i need help with

I have an older iMac 2006 running Lion happily (well sort of)
kinda half wishing i had stayed with SL as was a change for long time Mac user but happy with iCloud etc for general ease of use

now this is my only mac and want to use my eyetv again but since upgrading to Lion i cannot run Eye TV2 and need eye tv3
there is a discounted EYETV 2 to 3 upgrade but need to run eyetv2 to take advantage of this. ELgato have confirmed this and i would have to buuy the full version without going back to SL and run eyetv2

i have a SL restore through time capsule, can i go back (backing up files etc a given)
rune eyetv2, upgrade and then come back to Lion through time capsule??
Im guessing i could do this and then re download and run lion and start all over but thought id ask about time capsule