Garbage Disposal Refuse Backing Up Into House

Hi All

First time poster here and I'm a bit frazzled.  I'm hoping someone out 
there can give some advice on a remedy for this problem.  I'll do my 
best to describe it.  My story goes...

I noticed the carpets were wet in the lowest level of our house.  We 
have a bathroom and a laundry along with a floor drain in the laundry.  
There are four carpeted rooms along with a carpeted hallway leading to 
three of the rooms. 

I thought my kids had put something in the toilet to overflow but that 
was not the problem.  Then I had noticed a floor drain in the laundry 
room had what looked like garbage disposal refuse that spewed out of the 
drain under enough pressure to blow the plastic cover off. 

I think there is a blockage somewhere between the kitchen sink and this 
floor drain.  I had also noticed some refuse that had come up out of the 
shower stall drain too - but not nearly as much.  I had run the 
dishwasher twice today and had used the disposal quite often.  Could my 
line to the sewer be blocked?. 

I think I need to call someone like Roto-Rooter(sp?) but I think I may 
be able to work on this problem myself.  Any help is greatly appreciated.