With 15 amps your garage is only wired for basic lighting and possibly very minor hand tool usage. The wiring should be suitable for a light or 2, and a garage door opener, but not a workshop.
Ideally to have a good workshop, each major power tool should have it's own circuit. This is especially necessary if you plan on running more than one tool at a time.
You need to add aditional circuits and wiring to the garage. Do NOT change the circuit braker to a higher amp rating. You will no longer have a protected circuit. It would be a fire hazard and your insurance might not cover damage if you do improper wiring changes.
If you were just a "weekend warrior", occasionally using the saw and other power tools, and do not overload the circuit by using multiple tools at a time, you probably could solve your problem with just adding a new 20 Amp circuit and a few outlets in convienient locations. You need to verify how much current each tool requires by looking at the nameplates.
For more extensive use, I would recommend taping off the house panel with a 60 to 100 amp 2 pole breaker and having a small panelboard installed in the garage with seperate circuits for each major power tool.