Hello / hyvä !
Did you ask the cycle club of Fin or of Helsinki ?
They, I think, know much more as we here, far away from your country...
You can find the adresses of cycling clubs in Fin by the European Cyclist Federation ECF This Website is written in english language, so it will no problem for you!

I know, that´s very difficult for you, to find good quality parts or complete bikes in Fin, the best chances, I think, you´ll have in the capital Helsinki.
I know there only 3 shops, one was Intersport, the others were nearby an trekkingshop (5 min by foot) from the esplanade. But I don´t know they´ve Trek´s

Best wishes back to your nice town from someone, who was for five times there !