You are responsible for maintaining a stateless web-based API deployed on a single Compute Engine instance in the 'europe-west2-a' zone. The Service Level Indicator (SLI) for service availability is falling below the specified Service Level Objective (SLO). A postmortem investigation has identified that requests to the API frequently result in timeouts, primarily caused by the API experiencing a high volume of requests and running out of memory. Your goal is to enhance service availability. What steps should you take?