2009 impreza no turbo
 

Threw misfire code po302, po303,po304 po026, and po028
had terrible oil leak prior to these codes and then one day started slowing down and she stalled. Started up but sounds like a rod knocking. Will drive but as soon as slow down or have to turn stalls again My dad said he thinks it spun a bearing and rod is almost gone.
my question is what's the best way to go about fixing it fast and cheapest. Whether it be new motor or parts.
Thanks in advance

How bad was the prior oil leak and was it driven low ? Drop the oil and remove filter and cut it in half and have a look if there is any metal fillings in there. That will give you a good idea as to any damage internally. Running low on oil will cause damage to bearings quickly followed by everything else. Have a look at filter I’d say them go from there.