Q: Car keeps cranking over when not holding key, but still wont start

It sounds like you have 2 problems here, the starter and an engine stalling problem. The starter problem is probably the starter solenoid, a power switch (integrated into the starter assembly) that takes a small current from the ignition switch and engages a large current at the starter. The contacts in the solenoid can burn over time, "sticking", which can cause the starter "run-on" like you described, and a "no crank" condition, because the same burned contacts don’t pass heavy current very well. The poor idling may be due to a dirty idle air control valve, dirty throttle body, or air leak in the intake system of the engine. I would recommend having YourMechanic dispatch a mobile, professional mechanic to your location to do a (Starter Replacement)[https://www.yourmechanic.com/services/starter-replacement] and car starting trouble inspection.