The Knicks need to make the realistic adjustments they can before the playoffs hit
Clearly, the defense is poor, which is to be expected, the only size at Center is gone, and two good wing defenders in Gallo and Chandler are gone. This team isn't going to be able to stop any pointguard with a gimpy Billups, and sizey pointguards can still dominate Toney just because of his lack of height.
If the Knicks aren't going to make any Roster moves (which is highly likely), then they need to switch to a better suited starting lineup. Going with Billups, Fields, Walker, Melo, Amare is the best option. Amare needs more space in the paint, like he had when Moz was there, people respected that he would attempt shots, which with Jeffries or Turiaf you just don't have that. Moving Shawne Williams into a starting position is the wrong move because he will still need to lurk inside enough to not pull his defender. If Melo switchs to the four, he will draw his defenders where ever he goes on the court, letting Amare go back to being able to do damage in the paint.
It also helps out Melo, who is at his best when he can get a little breathing room. If you look at the makeup of the starting lineup for Denver when Melo was there teams couldn't put too many doubles on Melo with Nene in the paint and both Afflalo and (then healthy) Chauncey gunning from the outside. Bringing Walker into the starting lineup brings the same style to the lineup. The Knicks can have two gunners on the outside with Fields and Walker (and their best two perimeter defenders), Chancey attacking the rim, and hovering around the perimeter if the team needs space on the inside late in games, which lets Amare and Melo handle everything inside and midrange.
This team can still get it done, but they need to accept who they are and try to run teams out of the building with Scoring, having a short defensive center does not work, and Williams isn't athletic enough to be the 3 in a D'Antoni System. I'd love to see the Knicks let go of someone on the bench (Roger Mason gets my vote, eats Walker and TDs minutes anyway) and sign Earl Barron, so they can get some scoring out of the 5 spot. But the Chemistry is already frayed enough as is, just go small ball, none of the teams the Knicks would face in the first round are size heavy on the inside anyway (Celtics gave away their health size, and that's the Heats main problem), so that seems like the best option if that first round upset is still what we are questing for.
Note: Assuming we don't drop to the 8 seed, Boozer and Noah would have a rebounding fieldday.