As mentioned, there are some sellers on ebay, K&N makes air filters, some have found aftermarket oil filters but the hydraulic fiters are a little harder to match up. Kioti oil filter prices are fairly reasonable so I use them knowing they meet proper flow rates and specs. Other brand specific parts are no where to be found.
I've had very good results with several Kioti dealers in the states. If you call them and advise what you need, they are happy to charge your credit card and send you any part. Usually, they will also give you some advise on the particular job/repair you are doing if you ask. Some dealers have the general maintenance items (filters) on line but that's it. I have always received parts in less than a week.
The members here each have dealers they like to work with. If ordering from the states is a possible way for you, contact information can be provided by the members.