<p>GRE really won’t do much to cover for your GPA. The GRE is mostly just a competency test and isn’t weighted that heavily. Also, I don’t think engineering departments will care about GRE subject tests since hardly anyone else applying will probably have them (other than those applying in different departments at different schools).</p>
<p>The best thing you could do is get some sort of work experience to show your competency, try to take graduate classes as a non-degree student and do well in them, and try again in a few years.</p>