Awsome! That little machine is a bigtime performer. I have ones 4x its price, and I'll vouge for the Little Green any day of the week. Just fill it with hot tap water and go to town. Yeah, you could pretreat, or just do it all with the wand. Either way, I believe you have a great shot at removing those stain-rings. For the pen ink, try hairspray.
If you don't have any pretreaters or chemicals, use one teaspoon of laundry soap in the little green's fill tank. Add the soap after you fill with water.