It is time for some upgrading on my PC. I am on a tight budget. My PC is a modified HP Pavilion m9300t CTO Intel Core 2 Quad
Q6700 @2.66GHz 2.    8.00 GB Installed RAM 64-bit OS, x64 based processor Windows 10 Pro V 1703 OS Build 15063.483
I am running SONAR Platinum w/ Lifetime Updates, Drums and Keys by XLN, M-Audio TFP/Arsenal, Air Music Technology VSTs, Roland D-5, M-Audio Keystation 61es, Fatar SL-990 Studiologic Midicontroller, JBL 7.1
My PC has three Hard Drives: C: Solid State 118 GB Capacity with 44.2 GB free E: 7200 RPM Dsk 149 GB Capacity w/ 69.5 GB Free
and J: 3 TB WD Book (external HD).
I have recently purchased VSTs (about 70 GB) which have not been installed. I believe what I need is to reconfigure my drives. C: OS, D: SONAR, and E: Libraries. I'm guessing that I would eliminate the external drive (save it for backing up), and would benefit from at least one additional SSD, but ideally two ( one at least 128 GB, and the second ideally larger).
Am I looking in the right direction? I'd love a new PC with i7 and 32 GB RAM, but I can't afford that.

Get a bigger SSD for C:, put all Windows programs and VSTs on that.  There are many 240GB SSD drives available for under $100 at Newegg.
https://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100011693%204814%20600038463%20600038500&IsNodeId=1&cm_sp=CAT_SSD_1-_-VisNav-_-2.5%E2%80%9D-Inch_1
 
Get a bigger HDD for E:, and put all your libraries on that.  You could create two partitions there, say E: for sample libraries, and F: for Cakewalk projects.  WD Blue 1TB 7200 RPM SATA drives are running around $49 for the next two days at Newegg.
https://www.newegg.com/Product/Product.aspx?Item=N82E16822236339
 
Use the external drive for backups.
 
No huge advantage to a 2nd SSD, except maybe for sample libraries, to speed up loading samples.  7200 RPM is good enough for an audio drive and projects.