it is do able but will be a whirlwind!!!
If Shatabdi arrives well on time den your first course of action should be as follows:
the wagah ceremony is tied up with sunset, so you will need to be there atleast one hour before tht, so as to find a suitable seat. Sunsets are around 5:30 to 6:00 for this week... you will need 30-45 minutes to get there as well, so you can start with Jalianwala Bagh, then do lunch then proceed to Wagah border latest by 3:45 pm. After the ceremony you can come back visit Darbar Sahib/Golden temple in the evening... stroll around da markets...head for da station and wait for your return!!!
In my opinion its best that you get a taxi for the wagah border trip, I aint sure but you can see if the radio taxi's cover it.... 0183-5151515/6060606. otherwise you can hire dem outside the station. For jalianwala bagh and Darbar Sahib/Golden Temple you can do auto-rickshaw or cycle-rickshaw...
A shared auto is usually INR 10 so if you are goin for one all for urself it should be between 50-60 bucks one way!!!