Hotspot - walled garden ftp how?

Hi All

Well I have hotspot running ok , and I want to hotspot users have bigger speed trought mikrotik to my local ftp .
example:
local hotspot users — mikrotik — my network with ftp server — hardware router — internet
hotspot user have 128 kb speed to internet (created in hotspot profile) , but I want that users have in the same time speed 356 kb (or bigger) to local ftp server (this speed I want to regulate on ftp server - which have this feature).
Now I was try to put ftp host in walled garden , but bandwith is still same … 128 kb.
So I know that I must put some rules into firewall , but I m not sure which , or how.
Does anybody have some examples , or sugestions?

Any sugestions?
Nobody ?