How do you get a regex from this DFA?
By reading a 0, your DFA switches its state from right to left, 
By reading a 1, it switches state from up to down. 
So to reach your final state $q_3$ your DFA has to read an odd number of 1's and an even number of 0's.
Therefore your language is $L=\{w \in \{0,1\}^*|  |w|_1 mod  2 = 1, |w|_0 mod 2 = 0  \}$