take your old seal to any decent o ring place(there are quite a few in the gta) and match it up with a viton o ring(which are common in industry)...
Id wager a lot you can find what you need....though not sure what you would do with the teflon seal part... you could also try the same idea.
Oring shouldnt be a problem...teflon seal may be.
some measurements the single vanos o ring size is M2.62X77.5 which is a european din size. (I just measured and compared my measurements to chart)
though better to compare with old unit.
the teflon seal ID is the 82.xx of the oring od.
these guys have a lot. Ive been to them for other car orings and matched things up
and they also carry a wide range of teflon seals.
If you dont do this ...Im likely to make the trip to see for myself.