The standard form of the given parabola is:
\[
(y - k)^2 = 4(x - h)
\]
The focus of the parabola is given by:
\[
(h + 1, k)
\]
Since the focus must lie between the lines \(x + y = 1\) and \(x + y = 3\), we substitute the focus into the inequalities:
\[
1<(h+1) + k<3
\]
\[
0<h + k<2
\]
Thus, the required range for \( h + k \) is:
\[
0<h + k<2
\]