First, your formatting of the data is not appropriate for such an analysis. You need to create a separate variable for each level of your within-subjects (WS) factor. So you would have Age (categorical variable;column1).......SOA (categorical variable; column 2).......IS1 (nominal vaiable; column 3)..... IS2 (nominal vaiable; column 4).......IS3 (nominal vaiable; column 5)........IS4 (nominal vaiable; column 6)........Reactiontime (continuous variable; column 7).
Regarding how you can run the analysis; use the "Analyze-General Linear Model-Repeated Measures" path to access the diologue box to run the analysis. When you click on it, you will first need to type in your WS factor (IS) and how many levels it has (4). Then, in appropriate order, define each level of your WS factor. After this is done, choose your BS factors and you are all set.
I hope this was helpful.