In part 1, your wing had broken on your Styrofoam plane. This was most likely not the only damage.
This session will deal with some of the other damage that may have occurred. The goal is to get your plane back in the air with the least amount of cost. Chances are that you have other damage relating to the aileron and possibly the rudder section of the plane. Unless your plane crashed with several rolls and created an un-repairable situation, then there is still hope at low cost.
Repairs: The most likely repair that will be required will be to the aileron on your plane. Depending on the damage, it will appropriate to repair or forget it. The aileron is almost too small to use the dowel technique for repair.
One of the best repair tools is clear packing tape. If the aileron is not too badly damaged, use the clear packing tape to mend it. This material is strong, cheap, and flexible to fit most any need. It also works well to adhere the aileron back to the main wing support.
If you still are at a loss due to more severe damage, then I would suggest that you obtain balsa wood that you can cut with a knife and then shape by hand to as close as possible to the original aileron. First, cut the length and width to the approximate dimensions as the original. After completing this, you will need to more precisely ensure the aileron will fit in its expected position and operate without obstruction.
Now the harder part. Your aileron will need to have an aerodynamic form that will replicate the original. To accomplish this will require some skill and labor on your part. The best way to carve the desired shape is to use a model planner capable of removing small amounts of wood without causing massive damage to your newly created replacement. You could also use the old fashion method of carving and sanding which will work just fine. As you work, continue to compare the original damaged piece vs. the replacement that you are making.
Once you are satisfied that the replacement and the original are close enough, then the task of mounting the aileron will come next. There are two things to consider, 1) Mounting the aileron to the wing and 2) The linkage that previously existed to drive the aileron.
On a Styrofoam plane, there are not a lot of options so begin by what was most likely holding the aileron in place from the start. Tape. Again, use the clear packing tape and affix the newly formed balsa aileron to the wing.
Next, connect the linkage in the desired location as close as possible to the original using either a two part epoxy or other glue that you obtain for this result. There are no silver bullets. You just have to do your best..