Ease of obtaining diminished value varies by state regulations the insurance companies are bound by. In Florida you can not obtain diminished value from your own company and as a result not at all if loss was your fault, but you can from the other or at fault company. In some states you get DV as a part of the loss. Before you spend money on an attorney who operates for pay, and you do not want an attorney getting part of your DV money, call the at fault company and discuss with an adjuster, use business tone, do not make unreasonable demands and this should be easy. Try to remember he or she, has already heard every threat, hard luck story and only wants to pay you and get rid of you, if you have money coming. I was that guy, if you used foul language, I hung up and did not call you back, ever. The only way our conversation continued was you caught me when you called and I picked up the phone cold.
By the way, although 14K sounds like alot of damage, on a $45,000 car it is not that much, less than 35% of retail value. Sorry you had the loss. Remember to KEEP that DV money for when you trade in the future because your car really is worth less than it was before and most folks need that cash to make up the difference at trade time.