First, the standard "professional" installation is limited to areas that are safely reachable with a 28' ladder (i.e., the roof itself is no higher than about 22' above the ground). A 3-story building is automatically a non-standard job, meaning: not free.
Second, mounting on that roof means mounting over the living space. No intelligent (or even experienced) installer will do that, because if the roof leaks, most customers will try to persue a damage claim against the installer, and leaky roofs can easily run up repair bills in the tens of thousands of dollars.
Third, if the dish is mounted on the roof, EVERY time the dish needs service, it's going to cost the customer custom fees. A 40' ladder requires a minimum of 2 people to use safely. DirecTV doesn't pay for 2 people, so the customer has to. DirecTV doesn't pay for a 40' ladder, so the customer has to. DirecTV doesn't pay for the extra time, safety equipment, etc. necessary, so the customer has to. Since most customers balk at paying, most of these installs simply don't get done. DirecTV is not for everyone or for every situation.
Fourth, a 138 pound 40' ladder WILL crush those rain gutters, especially once you put a man with a tool belt and a dish on it. And it will do so every time someone has to get up there. And whoever has to go up there to replace them is going to charge a bunch of money too. DirecTV will get the blame, and they'll just forward that to the installer's insurance, and he'll have to eat the costs. Smart installers will refuse for this reason alone.
Fifth, no intelligent installer is going to put the ladder anywhere but on YOUR area of the roof. You may not mind a crushed rain gutter to get your TV going, but your neighbor WILL.
My company does residential and commercial installs. We could probably do this install, but I'd probably charge somewhere between $500-1000 to do it. Having worked in these multi-story townhomes, I know what kind of hassles they come with. Running cable is extremely difficult, because it can't be done on the outside, no one wants it visible on the inside, and often there is no attic access from the units themselves, since the attic is shared with multiple units.
But, honestly, I'd advise you just to stay with cable, unless you're prepared to budget several thousand dollars over the next few years for installation and maintenance, and be willing to compromise a bit on visible cable in the interior. Townhomes come with lots of compromises, and getting (or not getting) satellite TV may be one of them.
I can almost assure you that you aren't going to get a free install here from anyone, and if you do, it won't be safe, weatherproof, or compliant with your HOA.