It's got your growth factor around 4. So assuming that just means that you'll quadruple your yeast, and assuming that growth factor is solid over multiple starters (it'll probably go down as your pitched population increases), it would go like this:
Pitch the yeast into first starter (10 billion cells -> 40 billion)
Decant, pitch into second starter (40 billion -> 160 billion)
At that point you might be comfortable with pitching. Some people just pitch the 100 billion from the vial and make beer, though you're more likely to produce just alright beer or to have some problems along the way. My guess is that since the growth factor will decrease, you might want to do yet another starter (but probably a smaller one, like 1-1.5L).
All in all, that's a lot of work, time, and DME. Just buy new yeast.