It will be **65%**, as the 30% boost applies to the amount **drained**, not the amount it *will* drain.

It says **increased**, which can,*most probably*, solve our problem.

Also, Leech Seed, if dealing 10 damage, will damage 13 with a Big Root. This is a similar case, with **30% of the HP healed will be added to the total healing.**

Look here for the Leech Seed example.

This question also tells a lot(your own answer) : http://pokemondb.net/pokebase/69224/does-the-root-make-draining-moves-more-powerful-just-heal-more

Note : This is what I feel, after having done the Math. However, if anyone differs, then, I won't deny, considering this is a tricky question. Also, **I might be wrong for all I know.**