robbie, you should post your question in the Legal section so as to get the reply of Fabio Guzman, the attorney who answers questions in this section. Unlike most of the rest of us, he does not read the other sections. On matters related to the law you are better off with an informed answer than opinion.
I suggest you read the detailed explanation that Fabio has posted on his website regarding obtaining residency
http://www.drlawyer.com/txt/articlesimm.html You will see that one of the requirements for both the provisional residency and the permanent residency is "Notarized letter of guarantee from a Dominican person or corporation or a permanent resident"
I got residency nearly 20 years ago and a letter of guarantee was required for both the provisional and permanency, same requirement as is still in existence today.
Makes sense when you think about it and it is not unlike what is required in most other countries of the world. The US is lax about illegal immigration, but most countries are not and they require evidence of solvency.
If you note in Fabio explanation, the guarantee letter can be from a permanent resident. Among the people you know here it is likely there are some with permanent residency who may not even know that a guarantee letter from them is suifficient.
Someone has suggested asking the attorny who helps you with property purchase and that is worth considering. But if you have friends who have permanent residency, talk with them about helping you out with the letter so that you can get your residency.