Look into using Hired.com (note: not all that apply get approval).

I used it when switching jobs and it help me land a 50% salary increase. I am not exaggerating that. It showed all the possible salaries that companies were willing to pay me before negotiation and interviews started. It helps show what you may actually be worth to employers. Obviously your milage may vary but 40k is extremely low for computer science. Now it obviously depends how good you are etc. For reference I struggled straight out of school as I did computer science minor with another computer degree as my major. However, once I landed my first job ($65K) it has been upwards every since. Best of luck and reach out if you'd like (or anyone else in a similar position).