With a brute force program solver written in C#, I found a solution with sum 366:
3 11 5 | 19
37 17 13 | 67
7 31 23 | 61
---------+---
29 47 59 41 | 43
TheI let the program still runs, thoughrun until the top left corner was 61, so I'm pretty sure that there might beare no better solutions., but feel free to look for yourself:
Source code at PasteBin (you might want to change the initial value of recordSum
to something bigger than 366 to actually get some results).