My question involves a traffic ticket from the state of: Oregon

So, I've been doing research on this particular issue and I can't seem to find any clear answers that will help me figure out this case. Any advice would be greatly appreciated.

I'm driving home at about 10:30 at night in Eugene, Lane County, Oregon. I approach a round green signal to turn left from a two way street onto a one-way street (using appropriate signaling and turning into the correct lane). Just as I'm about to enter the intersection, the light turns yellow but I was too close to stop before the crosswalk. So, I enter the intersection as the other car drives through the yellow light. The car goes by, and I finish my turn and vacate the intersection on what was probably a red light, although I didn't see. I then crossed two lanes to turn right on the next street, and after having made that turn was pulled over by an officer.

He says that I ran a red light and changed lanes too quickly. I asked for clarification regarding changing lanes because I didn't understand what the issue was, and he said I didn't signal for long enough before changing both lanes and it appeared that I wasn't looking where I was going. I didn't say anything or ask about the supposed red-light running. After taking my info for about five or ten minutes, he ended up giving me a warning regarding the lane changing, but wrote me up for "fail obey traffic cont dev (stoplight)" under rule "811.165." The guy was fairly nice and after explaining the regulations around lane-changing signals, he told me I could look into getting my fine reduced at the violations bureau.

First of all, I'm unclear regarding the legality of entering the intersection: I was under the impression that I should stop at the crosswalk for a yellow light as long as it is possible and safe for me to do so, but since it was neither, I was in my right to enter the intersection and then vacate it. Secondly, his description of the event both in words and on the ticket does not match the rule number he wrote down (811.165 discusses failure to stop for public transit vehicles, he probably meant 811.265 which discusses failure to obey a traffic control device), which seems like an inconsistency which may help me out.

So, in summation:

1) I am under the impression that my maneuver in the intersection was legal, although it could probably be easily argued that it was not;

2) The rule number he wrote down does not match the violation he described, and I'm wondering if that will lend me any help in the case;

3) He did also say that I had failed to signal properly changing lanes (which I believe I actually AM guilty of) but he didn't actually write me up on it, and I'm afraid that will work against me if I pleaded not-guilty.

So any advice would be appreciated. Should I contest it in court? I'm 18, have a clean record so far after almost two years of having a license. I have the option of going to the violations bureau to have the fine reduced from $300 to $175, but that's still way more than I can reasonably afford. Is there anything I can do? Thanks in advance.