Well, how about if we change yours perspective? instead to use/upgrade others people team, let's make yourself a team!
By now you must have very good ideas sprouting on your head, a good starting point is to choose a pokemon (does not matter if the pokemon you choose don't have competitive value, there's always a way around) and make a team around it.
This is a good check list you should want to take note:
o Steel Type
o Ice move
o Fire move
o Type to resist water
o Type to resist fire
o Fake Out user
o Fighting type
o Weather counter
o No more than 2 pokemon with the same weakness
The thing is, every player have an ideal playstyle that he/she find comfortable with, if I suggest pokemons to you, is very likely that I will suggest pokemon biased with my own playstyle. So first thing is to find your playstyle and make it work with your own ideas and with pokemons you like.
About the pokemons from Pokecheck, the only place where you CANNOT use then is in Real Life competitions hosted by Nintendo (the VideoGame Championship Series or VGC for short), any other place is good since the only problem with then (from Nintendo point of view) is the ribbon that pokecheck attach to all the downloaded pokemon. Keep in mind that I said "Real Life competitions" because the Wi-Fi ones hosted on Nintendo Servers DO allow you to use pokemons with ribbons.
About the competitions on smogon, they are ramdonly held so you need to keep cheking out the Wi-Fi Tournaments Forum to know when is the next one. You can also use the Wi-Fi Battle Finder that is on the main page (in the left side, under the "Train and Battle" section, the last one)
For the Teams, you could check the RMT thread but need to be sure they have the "VGC" category. For example here is a team I posted a few weeks ago, is a Drizzle team so you will feel confortable with it.
For your current team, the combination of Whimsicott + Terrakion is a VERY well know combination and like every other popular combination people have designed strategies to counter it. So that's why is better for you to keep Weavile since in case your opponent counter your beat-up strategy Weavile have an offensive precense you can use in your favor, Whimsicott is a cottom ball (how hard you think a cottom ball can hit?), a complete Taunt bait cottom ball.
With weavile you don't even need to lead with Terrakion + Weavile, you can keep Terrakion in the back while Weavile score some KO's agains the so common dragon types, and then swith Terrakion in the same turn your weavile use Beat-Up. The Key is to be unpredictable, since most players can wait for the Terrakion + Weavile combo and bring they counters at the beginning of the match if you take out one of those pokemon you can just sweep with terrakion now!
I think that your team is very solid and if you got to 48 victories you sure have what it takes. From my point of view you just need a "little" help, so i can advice you to read this article. There you can get good strategies to beat that Ingo guy.
I will give you a few hints in advance: There are 2 ways to beat the battle subway, the very easy way and the very hard way. You have been using the very hard way. The very easy way is to get a DrizzleToad, Scarf Water Spout Jellicent, a Swift Swim Kingdra and a Technician Scizor. Just set Drizzle and nuke all those shitty NPCs.