If you can afford/justify it, definitely get a (quality) replacement finder like pgc hunter suggests.
I still maintain the 40mm eyepiece at 22x could be a more cost effective/versatile alternative though. People use binoculars with higher magnifications than that, without finders.
I don't know how much you paid for your scope, but the price of a higher grade 5x24 replacement finder, which you don't typically re-use when you upgrade to a bigger scope, comes awfully close to the price of a new 114mm DSE no-name equivalent scope (CrazySales, DealsDirect, etc.).
If you ever want to upgrade to a better scope, you can still use the 40mm eyepiece. Note also that the difference in quality between the cheap Huygens design eyepieces that typically come with these scopes is most of the time very very bad (and usually not appropriate for the capabilities of the optics - too high magnification, just so they can claim '675x zoom !' on the box). If your eyepieces are labeled H or SR this is another very compelling reason to choose investing in an eyepiece, rather than a finder.
My educated guess is that the finder that's missing is one of those typical plastic 5x24 models, which, frankly, isn't that useful (I actually got two of these 'cheap' scopes with said finders - the poor optical quality and small aperture makes it kind of hard to find anything but the brightest stars). You would've probably been frustrated with the standard finder anyway.
That said, you're welcome to have one of my 5x24 finders (it's from a Celestron scope) - just send me a PM if you think you can use it.
Best,
