If you have to use an array, then you're going to have to write your own sort. If you KNOW that there will ONLY be 10 numbers, an insertion sort woulnd't be too hard, and fairly quick.
as to finding the two middle numbers...once the array is sorted, you would just want to get element 4 and 5. None of this sounds too hard. When is it due???
There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors