Lucia,
Do you have enough money to shell out 30 bucks? I have a Sonic Shaker SBP100 and it's came through for me. It's a portable vibrating alarm clock. It is also great for traveling as well. The alarm clock is so small that you could fit it anywhere but yet, the vibration is strong enough to wake you up.
You might want to check that out and see what you can do about this.
Sonic Alert - America's Leader in Visual Alerting Systems