My Yoda needs a New Engine. Suggestions?

[LadyMe]

The 22R I have been struggling with has blown a head gasket or head or something very bad (oil & coolant mixing, white smoke, black liquid coming out of tailpipe, smells, chugging, stalling, etc)... attached is a picture of the dip stick.

I've got some mobile mechanics coming over on Thursday to make the official diagnosis. I've heard people say "If it's a bad head or head gasket then get a new engine". Do you agree? If one of these things is the problem, am I better off dropping in a rebuild?

I would appreciate any advise on how to purchase a rebuild. I'm not trying to look for the cheapest way to get this done... I want it done right. I can find a few engines on ebay but I'm nervous about buying an engine online. They say it's compatible with my make/year/model but is there a way I can be sure?

Thanks!