electic,
Have you tried partnerships with your local senior centers, assisted living centers, hospitals? Try contacting the AARP to see if there are ways for you to connect with people that need your services. There are also local organizations for retirees.
I don't know if you have much in terms of advertising budget, but low-cost advertising would include Craigslist.org, Tribe.com, and your local Pennysavers. If you have more of an advertising budget, radio ads or local television ads may be appropriate. Advertising with the right radio station that can demonstrate reach into your target demographic can be VERY effective. In your case, I'd try the AM stations for a cheaper media buy.
Try to think like your target market. What activities do they engage in? Who do they seek or turn to for assistance, help, or advice?
Another way to think of it is to partner with those that serve your target market in a different capacity. As stated above, doctors and nurses are a good start... also, stores that supply medical and healthcare supplies... or local pharmacies... local libraries... I'm sure there's more, THINK CREATIVELY and go knocking on doors!
If you're sweating your day-to-day expenses while you're in start-up mode, I'd STRONGLY encourage you to talk to your local SBA (Small Business Association) chapter to get advice about financing. ALL SBA's will provide a level of FREE consulting to help you get on your feet. They're generally staffed with very helpful people who want to see you succeed. By getting financing, even at the level of a short-term small business loan, may buy you enough comfort and finances to launch your business properly.
Remember, as with many small service companies, your quality of service translates into strong word of mouth. Your customers know other people who are in the same demographic who may want to seek your services. Even if it's not today, good WOM means building brand equity, which means building business for the future.
To be honest, while people here can give you good advice, if you're really stressing about this... go seek professional SBA consultants. The answer to the question you pose translates to me that you haven't developed an adequate business plan. Here are links to FREE resources that are there to support you:
http://www.sba.gov/
http://www.score.org/
Best of luck to you!! I know it's difficult at the start, esp. when the road seems unclear, but there ARE lots of resources out there to help. Utilize them and PERSIST!!!