James- Soup will become your best friend. You might also try a dry mix called Scandi Shake - it mixes with milk and gives you 600 calories at a pop -and tastes pretty good. You'll get tired of trying to eat/swallow, but it's important to keep your calories up.
Check into your local Cancer Society office or United Way. They have really good resources and can be very helpful. Also, some of the larger institutions (Mayo, Dana Farber, NIH) have foundations that assist the uninsured.