How do I apply for Auto Injury Extension for less than $10000 without a Lawyer?

It sounds to me like your are asking for an extension to extend your statute of limitations beyond the expiration period, which appears to be July 30, 2014 based upon your question. A statute of limtations is the amount of time you have to file a lawsuit against all responsible parties. If you fail to file a lawsuit within this time limit against all responsible parties, your claim will be forever time barred and you will not be entitled to compensation. Progressive should have advised you of this by letter. For auto accidents, the statute of limtations is two years from the date of the accident. Thus, you must file a lawsuit against all responsible parties no later than two years from the date of the accident, or your claim is barred.
Generally speaking, there is no such thing as an extension to a statute of limitations, unless the person who caused the accident and any other responsible person would be willing to sign an agreement to extend the limitations period beyond the expiration date. And I have never seen an automobile insurance company agree to extend the statute of limitations in my experience. So what you need to do is find a lawyer ASAP who will take your case and file a lawsuit on your behalf no later than two years from the date of the accident. Or you can file your own lawsuit, but it will need to filed against all responsible parties within two years of the accident, or your claim will be barred. Go consult with a personal injury attorney in your area now. Any delay could result in your claim being denied as untimely.
Best of luck to you.