I happen to work extensively with adhesives and epoxies as a part of my day job. Here's the source I use for needles. They have a needle for almost everything, including brush tips that would be useful for inserts. They also have syringes with plungers. Make sure you use syringes with a luer lock, or thicker material will pop the needle off the end. You can also search "dispenser needles" on Amazon or Ebay.
If you are doing a lot of work with high detail, I highly recommend a pneumatic dispenser which can be found used on Ebay for reasonable prices. This allows perfect control over the amount of adhesive you apply.