1995 Geo Prizm over heats and leaks collant

A while back I was driving and the serpentine belt broke and by the time I was able to pull over safely most of my antifreeze had boiled off. Since getting the belt replaced I have noticed that my antifreeze in the radiator keeps disappearing. I have recently noticed a large puddle under my car after topping off the antifreeze. Later that week I was getting a strong smell of Antifreeze while driving especially at stops. Today I was forced to Pull over as my Engine Temp was beyond the red line. It seems there is a leak under my engine as I can see the antifreeze has sprayed underneath. After the raditor had cooled down I opened the cap and antifreeze sprayed all over the place. Brown slushy like goo, nothing like it looked when it was added. I'm going to have to get it looked at today but was wondering if you had any idea on what it could be, and what can I expect to pay to have this repaired?