Build or new engine?

[510-SR20DET]

Ok so i left my car 5 months w/o starting nor driving. Today i decided to turn it on for the heck of it, it didn't turn on, crank but didn't fire. I changed everything new (sparkplugs, battery even new gas) it just wont bugged. I busted out my compression test gague and found out that i have a low compression. ENGINE BLEW ITSELF EVEN NOT RUNNING? WTF?
Called some shops and they said it might be the head gasket, since it's been sitting too long, it might got rusted and went bad.
The engine is already on it way out, so i want to do something about it also at the same time but i dont know what to do. Should i rebuild it w/ goodies? or should i get a new engine? trying to keep the cost as low as i can. I already dump too much money into this car.
New s14 Sr20 is $1500 plus labor to put it in gonna be 2000 total. rebuild w/ Cp pistons, Eagle rods and blue print the block plus labor is gonna be around $2500 but it alot stronger than another stock s14.
What should i do?