I was trying to refrain from replying to this thread. First of all I am not sure if it belongs in this part of the forum, but most importantly I couldn't get rid of a credibility issue with the poster, from the back of my mind. He came to the U.S. when he was 8, but doesn't speak anything other than English. The sister came with him, but is now a U.S. citizen, how did that take place, marriage? He's been in the U.S. for fifteen years, but his writing (and what reflects of his thoughts) doesn't seem to correspond to a person who's been in the U.S. and Canada for so long. However, I temper those suspicions with his statements of bad parenting, perhaps poor schooling which might explain the level of writing.
Anyway, some advice would be to take advantage of Canada's excellent education system and try to improve in your education. Don't take it bad, we all have to educate ourselves for life more or less.
I also don't know what is your immigration status in Canada, but if you hold Luxembourg passport you should probably be able to relocate and work in UK or Ireland where English is spoken. My take is that you are also overstaying your welcome in Canada, as the way you explain your life and your case I don't see how you are in Canada in any sort of immigration status.
As for your chances to come to the U.S. I am not an expert, it would seem to me that you had a much better chance to fight your case inside the U.S. than outside. I don't want to sound harsh but if you had such a stake in this country you should have tried harder to stay in it. I mean if you have family and friends here couldn't you have collected some money to pay a lawyer? I don't know the details of your case, some of the things you say seem to make sense, but others raise question marks in my mind.
Do you have any criminal record? That would probably put the last nail in the coffin of your hopes to come back to the U.S. any time soon. It sounds really bad that your sister doesn't want to help you, but to be honest there is not much she can do. I think, even if she sponsored you I think you would be looking at 15 years or so of waiting in line. She could have helped you thought when you went through the immigration proceedings.
Most immigrants in this forum have left friends and family behind, it sounds bad, but this could be a chance for you to start a new life, don't marry just for the possibility of getting to the U.S., which might not happen soon anyway. Europe is not such a bad place to live.
Godspeed with your case.