Nufc need a better defence

Newcastle have struggled all season when it comes to defence, Boumsong has been abysmal,and the injury of Steven Taylor did not help our cause.
The back four kept switching and changing due to either injury or suspension all through the season. What we need are a few decent consistent and reliable players who will steady the back line. I would suggest out of favour Man u defender Silvestre. I cant think at the moment of anyone suitable. Does anyone have any suggestions?