Road bike for smaller peeps

Very good decision

Being a stupid size, it's even more important to get advice from a cycle shop - the bike I bought, a Trek Pilot 1.2 with a 43 frame, had been specially imported for a tiny lady and when she went for a fitting, she needed and took home the 47. Which was good for me, I ended up with a bargain 43 that's a perfect fit - and the fitting guy adjusted it to fit even better...
I got my bike from Sigma Sport - only because it was the only 43 of that generation I could find in the country... and I didn't want to buy without trying! They were so helpful, I'd drive the 75 miles for a service or another new bike from them again!

Try something from the Specialized Ruby range second hand. Or there are a couple of 43cm Kinesis frames on EBay. KR210-L is the model number. Lots of budget left in the kitty to fit with say a 105 groupset and a decent set of wheels and crankset. Geometry on their website. The frames are also available quite freely by googling Kinesis.
I am 5ft 3ins and have a very short leg and am on a 49cm Ruby Comp female specific even tho I am a bloke and love it.
Cost me £497 all in by careful Ebay buying, all parts either immaculate s/h or new, apart from the seatpost which was a mistake slight dent in the carbon which is safe but makes me nervous and no offset. and will have to be replaced.

Right i'd state straight off, i know nowt about frames that small, but had a wee scout about for "bargins" for you around that kinda size and, yes the Aura is a womans specific road bike, but if you have a look about for some 2010 bikes you may just come across something cheaper with better specs, like this http://www.evanscycles.com/products/pinnacle/sentinal-30-2010-road-bike-...

Now i'm not 100% sure if "small" is small enough, but its just an idea, thats full 105 set up and a decent bike -£300 cause its last year, also have a look at any local bike stores, as its not a size thats always needed, there may be a few bargins kicking about in that size

I bought a Giant SCR in XS (43cm) because it was one of few bikes that fit me at 5'4". The Defy/Avail will have the same geometry though I'm not sure it has the mudguard-friendly clearance and long drop brakes of its predecessor, if that matters.

Kona do a wide range of sizes, the Honky Tonk is a practical-but-not-boring steel bike. There is the Scot Contessa, Specialized Dolce, and Boardman's 2011 models include an XS size. Islabikes are supposed to be kids' bikes but the road frames are big enough for small adults and very good quality.

I'm not sure that women-specific models are necessarily better suited to women cyclists. However, a look at Evans Cycles' list of WSD road bikes might help:
http://www.evanscycles.com/categories/womens-specific/womens-bikes/women...

I'd check out the Tifosi CK7 (will take wider tyres and guards) or CK3 which state they come in XXS sizes. Also the Giant Avail and I think Trek do an xs size?

My other half has a CK7 audax, which is an excellent bike - fast enough to be a 'proper road bike' but will take guards and winter tyres and even a little light touring).

I'd also definitely recommend a full professional fitting service to be sure of sizing (some bike shop recommendations can be way off). We had it done at AW cycles in Reading (despite living in Wolverhampton) as we were really struggling to find bikes which would fit her. It worked out really well and the bike fits brilliantly. You get the fitting charge refunded if you buy a bike as well, and they'll change bar, stem etc... at no extra cost if needed so that the whole bike fits properly for the type of riding you are doing. Details (and a fetching video of Rikki, the guy who helped us out) here - http://www.awcycles.co.uk/buyers-guides/fitting/index.aspx

Hoep that helps?

Phil.