Fixing low SG on bottling day?

Today I brewed an APA with a target SG of 1.046, but for some reason my efficiency was off by about 20 points and I ended up with 5.25 gal. of 1.035 wort. I've never had to add DME to adjust the gravity before, so I was cocky and figured this would never happen to ME. In other words, I had no DME on hand, and my LHBS had already closed for the day. I figured instead of an APA, I'll just call it an ordinary bitter, and pitched my yeast.

But it's bugging me that I'm not going to end up with what I had originally planned to brew. I haven't decided if I'm going to do this or not yet, but theoretically, could I boil about .25 lb. of DME in .75 gal. water, pitch the same yeast strain in that, and then blend the two together in secondary? Or even on bottling day in my bottling bucket? The math seems right, but I have a nagging suspicion there's something I'm overlooking here.

I think it'd be ok whichever you decide. But if it was me, I'd boil it up ASAP and add it to the active fermenter. The yeast will eat up that DME, too. I wouldn't bother for .25 pounds though- that's almost nothing in a 6 gallon batch. One pound, though, will raise 5 gallons .09 points. So, if you have 6 gallons (if you add .75 gallons of water you'll have 6 gallons total), you might want 1.25 pounds DME to add .09 points.

I personally wouldn't bother, unless the IBU/SG was completely messed up beyond repair. What was the recipe?

Thanks for the quick response and for pointing out that my math was off on the DME addition. Here's the recipe:

Size: 5.28 gal
Efficiency: 78.35%
Attenuation: 78.7%
Calories: 151.73 per 12.0 fl oz

Original Gravity: 1.046 (1.045 - 1.060)
Terminal Gravity: 1.010 (1.010 - 1.015)
Color: 8.9 (5.0 - 14.0)
Alcohol: 4.73% (4.5% - 6.0%)
Bitterness: 28.73 (30.0 - 45.0)

Ingredients:
8.5 lbs Pale Ale Malt
7 oz Crystal Malt 40°L
.5 oz Columbus (12.2%) - added during boil, boiled 60 min
.5 oz Cascade (5.9%) - added during boil, boiled 1 min
4.0 oz Apricot (extract) - added on bottling day
1 ea Fermentis US-05 Safale US-05

I was shooting for somewhat low IBUs since I'm adding apricot extract, that's what got me thinking about fixing this batch. I was paranoid about adding the DME in the primary during fermentation, not sure why now, though, you're response makes me think I was just worrying too much. That would make life much easier.