When is it expired?
Extending a work visa is always an option, but I don't think you can extend for very long, and you'd darned well have a good reason! You don't have a tourist visa, so you can't extend that. And, only immigration can tell you whether you can convert to a tourist status in order to stay.
If you have already worked here for a year under that visa, you can try to get several part-time jobs and use them for "self-sponsorship" renewal of that same visa. Just don't use the word self-sponsorship. Explain you have different income sources, and prove that they are guaranteed, just like your original sponsor. The amount you need to prove varies with immigration officer, so be sure it is at least subsistence wages.