I don't know if this would help in any way due to the different currencies, but probably there are people that won't donate due to not having a paypal account. If there was other way to donate maybe they would, some years ago I played a game called Tibia, and they actually let people know their (developers) address so that people without paypal accounts and such could be premium members too, the thing is, it gets kind of expensive to send money to another country, you would probably spend more money sending the donation than you are actually donating, unless you donate like 7€ or $ (you get the idea), I have no idea how much money do people donate for each donation they make, maybe this could work, but then again, the currency can be a problem :S
About the server hosting and stuff, sorry but I don't know what to say because I don't have experience with that kind of stuff, the only thing that occurs to me would be a different website/look for the game that would not require so much CPU (I don't know if this is even possible, I'm just trying to help >.< )
And yes probably the ads would help alot :S
Btw happy birthday thrall