Among the current requirements for a residency is that the applicant must have $500,000rd (about $30,000usd) either in a Dominican bank account or invested in the country such as a business, home, etc. It would seem that your retirement income alone is not enough to meet this requirement. A DR lawyer or financial advisor who is aware of residency requirements can best interpret this for you.
Also, despite government proclamations that the residency application process is easier, even as long-time residents speaking the language, we GAVE UP after the expense of staying almost a week in Santo Domingo and turned everything over to our corporate lawyer to finish the application process which starts with the Visa.
Even when we went to the Dominican Chancellery to apply for the Visa, I was denied entrance because I had on Bermuda shorts and sandals (there is nothing on the Visa application sheet regarding a dress code required for entry into their building).
Also, a little known and PUBLICISED fact is that after one year, the ENTIRE process must be repeated at the same cost. That will equal, for us, a lawyer's cost alone of $50,000rd (a bargain-2 for the price of 1), not counting the $100usd daily average for us to go to the capital,...add another $1,000usd or so.
My advice,...get the 10 year special Visa that ECH suggests further down in this thread,...and get it BEFORE you leave your home country; dealing with the current PRD government bureaucracy is worse than the last government, despite all the PLD's failings.