Neet to look at rows both before and after current row

In my current application I have a field in a table that has a value
that is calculated. The problem is that the calculation depends on
knowing the values of the same field in the row from the table that
occurs before the current row as well as the value of the same field
in the row after the current row. I know that through brute force I
could do the following: (remember... this is just pseudocode)

   Table1.InsertNewRow
   Table1.Prior
   Store field value found in current row
   Table1.Next
   Table1.Next
   Store field value found in current row
   Table1.Prior
   Calculate new field value using the two previously stored values

Is there a simpler way to look at values of fields in the rows prior
and after the row I just inserted?