Well, you are in a funny place with this machine and heading on a potentially slippery slope.? There is no easy way to say this so I'll just say it.!

The machine is not strong enough for a proper spindle and the spindle you link to is a toy in reality which I wouldn't waste money on. My advice would be to make use of what you have, save the money you would spend on a spindle, and put it into buying a better machine.?

The slippy slope I refer to is the fact that when you start to upgrade weak machines like these it quickly highlights other weak areas and before you know you are so far into upgrades that you could have bought a much better machine with the money without all the hassle and downtime the upgrades take.

It's a very common mistake new users make so the best advice is to use the machine without spending any money on it, then cut your losses and buy a better machine.