Installman,
I wish you the best. Give me a call through my site if you'd like to talk. Here is what I would do:

I would take pictures of all of the installations I do from now on so that you can post them on your upcoming site. I would hire someone part time to develop this site... a college student kind of familiar with building sites that you could pay hourly. Let them build it out of a template you pick out that you think looks professional so that there is little room for error and you can keep the overhead down.

If possible, I would call up or go in person to old installations I have done and check up on how it is working for them. This could give you another opportunity to build up a portfolio to show prospects. Also, the store owners may have a contact for another prospect. I would look back and identify the most successful installs I had done. I would break down the installs by category and where I got the lead from.

Where are you getting your business from? Think of similar untapped sources. For instance: commercial leasing companies... maybe you could work a deal where they could offer your services as an option for new retailers.

Get in touch with all of the retail designers and consultants in your area of operation. Let them know you exist and that you are prepared to implement the plans they create. Maybe you could throw something in about your understanding of store plans and your ability to make it reality. Cite other projects you have completed.

If I were you, I would call every major store fixture company in the nation and let them know that if they ever need installs in your area, you are willing and ready to work with them, while citing your previous work.

I would join my local chamber of commerce. Sometimes they are good sources. I have never had any success with local SBA though.

I would contact local mall supervisors and sell my ability for discrete installations and my willingness to work after hours if necessary to reduce shopping interruptions.

I would send a letter to all of my old customers saying, " Hi, I installed your fixtures or I installed fixtures for one of your customers. I hope your business is a great success in the new year...."

Do trade shows happen in your area? A recurring job might be setting up booths for vendors. Union regulations might not allow this though.

Good Luck.