Unless you have some sort of preexisting condition, are a newborn, or sickly, there's no reason to concern yourself over the amount of mercury in fish.
According to the online calculator, I was in the "acceptable" zone even when I ate a can of tuna virtually every weekday. There are higher levels of mercury in albacore tuna, but generally speaking most people are going to be just fine.
Just make the ramen and add a can of tuna. You can also add a mix of frozen vegetables. (peas, carrots, etc.)