You can't get conditioning once a week. It's got to be every day or every other day. Also, the conditioning has got to be effective(for example, instead of a long distance jog, you want to do sprints and indian runs).
You should probably also brush up on your leadership skills.
Lastly, you've got to get rid of the weak players. A lot of people join teams thinking "wee, paintball all the time!!" but don't want to put work into it. You've got to get rid of them. Tell them: "you keep missing the conditioning and practice I'll hand you your walking papers."
Are you the team captain or are you just the only guy who seems to really care? You need a team captain, to handle drills, paperwork, and speak for the team; and you need to convince them "you don't work hard, we don't need you." It doesn't have to be negative or an ultimatum, but you've got to make them realize being on a team isn't recball; practice isn't supposed to be fun, it's working towards a goal.
Also, let me go ahead and plug my thread in here, you might want to read it: http://www.pbnation.com/showthread.php?t=3750737