Washington State no longer has a grand larceny statute; the grand larceny statute has been replaced with Theft First and Second Degree. The consequences depend on the level of the charge and your criminal history. The remaining questions here would take a book to answer, and do not provide enough specifics for an intelligent response.
I don't practice law in Washington State, but let me answer your easiest question, "is there any chance of me winning my case?"
The short answer is that laws are very technical and as judges often warn accused persons, "It is almost never in your best interest to represent yourself."
Take that advice to heart and find an experienced lawyer in your community. If you can't afford an attorney, ask for a public defender when you get to court.
Hopefully, you heeded the advice given to your attorney, and you consulted with an attorney. It is worth a few hundred dollars to get an answer to your questions.
Remember, a citizen can bring matters to the attention of law enforcement authorities, but it is almost never the case that a citizen can get a charge filed, certainly not a felony. The police will make that decision, and then it has to be acted upon by a prosecutor. This is why you need a lawyer, because you will be facing a lawyer who is not working with you, but against you.
Good luck. Semper Fi, Patrick McLain
In you are charged in Washington, the charge is like to be theft, as another commentator posted. In Washington, theft of property or services valued at $1500 or more is charged as theft in the first degree. There are also provisions that are specifically related to vehicles, firearms, and retail theft. The consequencs vary enormously depending on the amount involved, the circumstances, whether you have a good defense, and other factors. As for winning your case, no lawyer can guarantee you that. If someone does make such a promise, that's your first clue that he or she is not being straight with you.
You asked about finding a good lawyer. If you live in King County, you can contact King County Lawyer Referral for a simple referral to a lawyer for some basic advice before you make a decision on hiring. You should also consult with friends and family for referrals. If you look for a lawyer on this web service I recommend you focus on the specific elements of a lawyer's background, such as work history, experience, and that sort of thing. I don't think the ratings tell you much. And keep in mind that many fantastic lawyers don't have information on this site at all. So if you get a referral to a lawyer, you meet with the person and feel confidence and trust in him or her, don't worry that there's not lot of info about that person on this site.