Insurance doesn't cover 300,000. If we settle out of court, what timeframe would be considered reaso…

Insurance doesn't cover 300,000. If we settle out of court, what timeframe would be considered reasonable? They're willing to return half within two weeks, and the rest at an unspecified later date. A month? Three? Six? What would be a normal demand for a timeframe? We want this resolved quickly. The at-fault party is stalling: no money, pension. But they took their car for repairs. Meanwhile, we've been taking buses, walking, and using taxis for a month and a half – the taxis are infuriating with their prices, refusal to accommodate my car seat, and bringing a car seat for older kids for my infant...