"the broadband itself is the problem"
you already have done everything you can except changing ISP's (assuming you have a choice of more than one).
the ping will increase the farther away from you the server is. getting 10ms for everything is impossible, the other end has limits too and you will be limited by them. while your connection MAY be able to get 10ms the other end may be limited to 50 or 200 or...
ping depends on the gaming server you connect to, how distant, how busy, how congested is your network node, how busy is theirs? All of these play into the ping.