What to do This Winter- Washington Nationals

I'd like to start an offseason outlook series beginning with the league's worst team: The Washington Nationals.
Currently 55-103, their situation isn't exactly desirable. However, they have had excellent seasons from Adam Dunn (.268/.398/.532), Ryan Zimmerman (.286/.358/.518), and Josh Willingham (.265/.373/.508) which provided some good pop in the middle of the lineup. The rotation looked good early on, but Tommy John surgery to Jordan Zimmerman, and a poor showing by Collin Balester sidetracked them a bit. John Lannan has been a bright spot with a 3.38 ERA and 4.69 FIP albeit with an alarmingly low 3.88 K/9.
So what should they do this offseason? Sell high on Dunn, who is batting 20 points higher than his career average, and Willingham, who is on his way to career highs in OBP and SLG? With J. Zimmerman out most or all of next year, they may hope to wait until 2011 when Stephen Strasburg has at least part of a year of major league pitching under his belt. Although, signing a middle of the rotation innings eater to an incentive laden contract may not be a bad idea for a holdover until then (think Rich Harden, Doug Davis, or Jon Garland).