Kim,
I used to be a roulette junkie when I first started going to casinos years ago. I'm certainly not an expert on the game, but I think I can answer your questions.
Yes, you can bet either red or black on the outside. If you bet on red, you will win even money if any red number comes up; you will lose if any black number, green zero, or green double zero comes up. If you bet on black, you will win even money if any black number comes up; you will lose if any red number, green zero, or green double zero comes up.
If you bet either green zero or double zero straight up, you will win at 35 to 1 only if that particular green zero or double zero comes up; you will lose if any red number, black number, or the other green zero or double zero comes up. If you bet the green zero and double zero as a split, you will win at 17 to 1 if either green zero or double zero comes up; you will lose if any red or black number comes up.
Regardless of its color, if you bet any number straight up inside, you will win at 35 to 1 only if that particular number comes up; you will lose if any other number comes up. As far as betting on the number 7 goes, it has only been a red number on any roulette layout that I've ever heard of - Eurpoean or American, but you can bet the number 7 inside and bet the color black on the outside at the same time if you wish. Just bear in mind that every bets stands on its own. Ultimately, you can't really shore up one bet by making a different bet at the same time because the odds and house percentages remain constant. That's a hard lesson for most roulette addicts to learn.
I think you might be a little confused about inside and outside bets. Most casinos offer a free roulette information card at the roulette table. I'd suggest that you pick up one of those and study the layout, the bets, and the payoffs before sitting down to play. Or you might pick up an inexpensive book about roulette or casino gambling in general. Just don't fall for any books that push some sort of worthless system. One of my favorite gambling books is The Pocket Guide to Casino Gambling by David Spanier. It contains an honest, straightforward section on roulette and it also covers every other casino game. You can find it at Amazon dot com by following the advertisment in the left hand column of this page.
Roulette is a better bet than any lottery game that I know of, but it's still a tough game to beat. You can make money at it from time to time, but I wouldn't count on making a living at it. Be patient, be smart about how you bet, and look for a table with a good rhythm. Don't sit down at a table where a bunch of idiots are betting massive amounts of chips that take the croupier a long time to clear and pay off. Also, avoid a table where the croupier is rushing the game and spinning if rapid-fire fashion. Find a table that's not crowded with players or chips where the game is moving in a smooth, even, comfortable flow. I know that might sound odd, but my experience has been that you're more likely to get on a good run at that kind of table.
Unless you're just playing for enjoyment, don't just stick around and play for enjoyment because the house edge will dventually grind you down. If you manage to get ahead at any point, start drawing down your winnings so you don't leave as a complete loser. If you get on a good run and end up way ahead, draw it all down and take off running!
Good luck,
aye'