Beautiful!!! It's not too late. Borders are part of the quilt top and get quilted too, so you want to add borders before quilting. The sleeve is usually attached after quilting, but leaving it in place the way it is would not interfere with quilting (as long as it doesn't get inadvertently turned underneath).
With the type of quilting you are talking about, I would encourage you to do it yourself using a walking foot. You could quilt around the figure, then echo quilt those lines or free-form quilt as you like. A walking foot straight feeds; however, you can easily use it to make curving lines by going slowly and moving the quilt sandwich as it feeds to the foot. Make a practice sandwich to test out what you want to do. Bottom Line thread (from Superior Threads) would work well for this, as it is fine but strong. You would probably want to use a size 75 or 80 Microtex needle.
Alternatively, you can consult with a longarm quilter about cost. Costs depend a lot on where you live and the experience level of the longarmer.