A quick search shows that prices for those dates are on the high side. I almost always stay at non-Disney hotels and I take 3-5 trips each year, so I feel like I have a decent grasp of normal prices. Some of the properties that are usually around $80-90 are much higher. (Example: The dismally-reviewed Wyndham Garden Lake Buena Vista is $137/night plus $25 resort fee. That same place is $89/night plus resort fee in a randomly selected date later this month.)
One question: Are you wiling to pay a resort and/or parking fee if the total is still around $140? Or, are you morally against paying those fees? It's okay if you are, but you're eliminating a lot of places in that scenario.
The other thing is that "contemporary" is a bit hard to pin down. Although I haven't stayed there, when I think contemporary in the Disney World area I'd maybe pick the Melia Orlando Suite Hotel at Celebration. It's located just a bit off Disney property. It's at the entrance to Celebration off Irlo Bronson Memorial Parkway (US 192).
Hotel website:
https://www.melia.com/en/hotels/uni...orlando-suite-hotel-at-celebration/index.html
Link to Bing Maps with Hotel Location:
https://binged.it/2rg8WVJ
According to their website, self-parking is free but they do have a $20/night resort fee. No clue about dogs...you'd have to figure that one out. They are slightly out of your price range, but not by a ton. On the plus side, you're getting a 750-square foot one-bedroom suite with a full kitchen. I know it's just you, but having extra space might still be enjoyable. Maybe you can stop at the nearby Public grocery store and buy some breakfast items. That might help make up the cost. The current pricing options:
$124.25 per night plus $20 resort fee (plus tax, no parking charge) = $144.25/night [Non-Refundable]
$131.00 per night plus $20 resort fee (plus tax, no parking charge) = $151.00/night [Free Cancelation if done 72 prior to Arrival]
For comparison, Disney's All-Star Sports Resort is $149 plus $13 for parking for those dates. As for "contemporary", I might categorize the Hilton Bonnet Creek Resort that way. It's $294 plus $40 resort fee and $27 parking fee. Also, there's the Delta Hotels by Marriott Lake Buena Vista. Their price is $161 plus $15 for parking.