How big of a starter can you make (what size is your starter vessel)?
According to Brewzor, you can do a 2000mL starter, crash it and decant it, then pitch that into a 2500mL starter and get your 237b cells. That's for a simple starter, setting it to "stir plate" says that even a 1000mL starter stepped up into another 1000mL starter will be over 300b cells.
So I think, if you're shaking often and you do it right, you can do a 1000mL starter, crash it and decant it, then pitch that into another 1000L of wort to get you where you need to be. 1L is a lot of "bad beer" to pitch into a proper batch of wort, so I would decant the second step as well and then pitch the slurry, but lots of people don't bother.
A 2000mL starter even on a stir plate will only get you 186b cells. You'd actually need a 4500mL starter on a stir plate to get it in one batch.
Having said all that, any starter is going to help you out. It's not like it won't ferment if there's not enough yeast. A starter is basically meant to (a) test the viability of the yeast and (b) get a jump-start on fermentation to edge out any contaminants that might have found their way in. If you're clean and careful, even just the original vial would do the job, it just might take a little longer.
Do what you can, don't stress about it. Oh, and I do recommend Brewzor if you have an Android device, it's quite handy and lets you do things like calculate step-up starters, which is a serious pain with Mr. Malty IMHO.