If you don't want to drive, you can always take the subway directly to Grand Central Station & hop a cab from there. It's about a 15 block walk, so I don't suggest walking to the pier. But its a straight cab run down the street to the waterfront. Cab will cost under $10 & the subway fare I think(??) is $2.50. You'll also get there faster.
I don't know the exact link on the net, but if you type in NYC Subway (or something along those lines), you actually should be able to pull up the Subway map. Pretty much all of the subway lines that were damaged during 9/11 are now up & running.