What eye drops are good for dry eyes and how long can you use the drops?

Depends. The type of drops which will be most effective for you depends on the root cause of your dryness. Your best bet is to be evaluated by an eye doctor who can recommend a treatment plan tailored to you.
Eye drops. Both refresh and systane are good brands. Of their products, i like the systane ultra and refresh optive the best. You can and will likely need these drop from now on if you have dry eye (since it is a chronic problem).