a stronger frame would be to find one that is a lugged frame
see how the tubes join this is a lugged frame
could it be fixed by a pro.... anything can be fixed/rebuilt if you have enough $$$
but it is worth it to pay a pro $45 up to $150 an hour to have them fix a frame on a sub $150 bicycle
to do that correctly would take a couple hours
Drill and grind cracks make fish plates weld cracks then weld on fishplates. Do other side of frame as well being one side already failed. To do the right and make it look nice will take some time.
Live life as its your last day... it just may be
Learn to do it right or how to fix it later, quicker to do it right the first time.