Is it true that our solar system belongs to another galaxy which collides with the milky way galaxy? I have just read an article about it here(http://www.greatdreams.com/2012.htm)(Scroll to bottom). I'm just a website developer, and I really want to know if this is really true.  I'm curious.
I'm pasting the content from it:

It turns out that our solar system appears to belong to another galaxy
  that is colliding with the Milky Way.  This was recently discovered
  when scientists were trying to figure sources for "dark matter" that
  would account for forces we can measure but not see visibly.  Using
  near-infrared (wavelengths of light outside human eye and optical
  telescopes) a huge sister galaxy circling the Milky Way was
  discovered. It's called the Sagittarius dwarf galaxy (SGR for short).
For those keen on the 2012 data, this is the reason our entry point
  to the Rift, center, heart (HunabKu) of the Milky Way is thru
  Sagittarius.  The two collide at that point. This explains why our
  solar system is at an angle to the plane of the galaxy and also why we
  dip above and below that center line every 12,000 yrs or so.

 A: Well, first of all, the entire site dedicated to the 2012 nonsense is a total hoax...  I suggest that you check out this site for more information regarding the weakness and outright lies of that hoax.
To address the copy/pasted nonsense...  The charlatans at the site you reference have taken real terms, and mixed them up in a word salad as to make any lies or fantastic tales they tell seem plausible.
For instance, the Sagittarius Dwarf Galaxy is indeed a real thing (although its discovery wasn't specifically tied to dark matter).  The dwarf galaxies that are around the milky way are not going to cause any particularly disturbing collisions in the near future.  Most of them just pass through the milky way on their regular orbits.  The most significant collision will take place in about 3 billion years when the Andromeda galaxy and our galaxy collide.  However, when galaxies collide, it's really just a gravitational interaction.  Very few (if any) actual stars hit each other).
Also, the solar system is part of the Milky Way, and from everything we know about it, it has always been part of the milky way.  It may get ejected in 3 billion years, but until then it shall remain part of the milky way.
The second paragraph you quoted is total nonsense (above and beyond the regular nonsense of that entire site).
A: Space.com confirms the Milky Way is in the process of merging with the Sagitarius Dwarf galaxy.  Given what we know and are able to measure, it is doubtful whether there will ever be proof we are actually from the dwarf galaxy.  However people have made some interesting observations such as noticing that our solar system is unexplainably tilted at 55 degrees when compared to the galatic plain of the Milky way. This "tilt" corresponds more closely with the dwarf galaxy than that of the Milky Way. http://www.space.com/12952-milkyway-galaxy-shape-galactic-crash.html
