How to restore and maintain a healthy sleep pattern?
Yang et al. (2001) study this exact question. They administered 6 mg of melatonin on Sunday afternoon to subjects that had delayed sleep-wake schedules for the two prior days. They found that


  On Sunday, melatonin administration increased the sleepiness throughout the evening and reduced sleep onset latency at bedtime. On Monday morning, subjective sleepiness was decreased in the melatonin condition.


Kolla &amp; Auger (2011) deal with resetting the internal clock for jetlag and night shift workers. Even though the situation is not identical, I think their main recommendations for adjusting the internal clock are relevant:


  Exposure to bright light in the hours leading up to the patient’s minimum core body temperature tends to push the internal clock later in time, whereas bright light in the hours immediately afterward pushes the clock earlier in time. 


(minimum core body temperature is usually 2-3 hours before wakeup time).
So in other words, in order to re-align from wakeup at 1pm to 6-10am one should wake up as early as possible, and go out to be exposed to sunlight (or use an artificial light source).

They also discuss the use of drugs such as melatonin and caffeine. 

References


Yang, C. M., Spielman, A. J., D Ambrosio, P., Serizawa, S., Nunes, J., &amp; Birnbaum, J. (2001). A single dose of melatonin prevents the phase delay associated with a delayed weekend sleep pattern. Sleep, 24(3), 272-281. Full text PDF
Kolla, B. P., &amp; Auger, R. R. (2011). Jet lag and shift work sleep disorders: How to help reset the internal clock. Cleveland Clinic Journal of Medicine, 78(10), 675-684. Full text.