The need for more - and more effective - campus ministry is great. You probably will never have enough volunteers to accomplish all that needs to be done.
Please keep in mind, however, that God has taken this into account and He provides all that is needed to accomplish His will in His time.
Perhaps you're trying to do too much, too soon. I recall one church that tried to start a campus ministry but it never got off the ground, in part because its leaders wouldn't let go of the idea that the church needed to reach all 20,000-plus students at once.
You campus ministry may be more fruitful if it does one or two things very well for a small number of students, rather than trying to do too many things for too many students and doing a mediocre or poor job. The students will be better served and your volunteers will have a greater sense of accomplishment, which may eventually lead to more volunteers who will be able to serve more students.
I can help your church recruit volunteers and match their spiritual gifts with your college's needs. Email me at greg@ourredeemer to learn more.