Dual monitors on ATI Mobility Radeon HD 4500 Series BO

I have, as far as I know, a unique issue. I recently had occasion to trust my Dual boot VAIO to the shop from which I bought it used. They were to find out why my Comcast Wifi kept dropping the link when I connected (a problem which I later found was an IPV6 implementation problem in 12.04LTS) . While there, I asked to have the hard drive backed up. Somehow, they were able to make the Windows 10 partition unbootable, although Ubuntu8 12.04.5 LTS Precise (kernel .115) still booted all right. I'll not trust that shop again!

In trying to resolve the Win10 boot issue, I reinstalled Win10. The result was that ONLY Win10 booted (I'll never do THAT again). After much work, I finally settled on using grub2 for Windows to get Ubuntu booting again. This worked, but my dual monitor capability disappeared. Windows displays the following information about the display controller:

Name ATI Mobility Radeon HD 4500 Series
PNP Device ID PCI\VEN_1002&DEV_9553&SUBSYS_9056104D&REV_00\4&1BF43939&0&0008
Adapter Type ATI display adapter (0x9553), Advanced Micro Devices, Inc. compatible
Adapter Description ATI Mobility Radeon HD 4500 Series
Adapter RAM 512.00 MB (536,870,912 bytes)
Installed Drivers aticfx32.dll,aticfx32.dll,atiumdag.dll,atidxx32.dll,atiumdva.cap
Driver Version 8.970.100.9001
INF File oem3.inf (ati2mtag_M9x section)
Color Planes Not Available
Color Table Entries 4294967296
Resolution 1366 x 768 x 59 hertz
Bits/Pixel 32
Memory Address 0xC0000000-0xFEBFFFFF
I/O Port 0x0000D000-0x0000D0FF
Memory Address 0xD0020000-0xD002FFFF
IRQ Channel IRQ 4294967293
I/O Port 0x000003B0-0x000003BB
I/O Port 0x000003C0-0x000003DF
Memory Address 0xA0000-0xBFFFF
Driver c:\windows\system32\drivers\atikmpag.sys (8.14.1.6264, 283.50 KB (290,304 bytes), 1/13/2015 3:20 PM)

Ubuntu 12.04.5 (kernel .116 to which udates upgraded me) only shows one proprietary driver for a sound device. When I looked in Software Center for a driver, it only shows one, that has almost universal condemnation by reviewers. I will be checking for an ATI website from which to get a driver, but thought that I would post this in hopes that someone else on here had encountered and solved this problem. Thank you.